Here I thought I was going to end this...
I don't agree it's dumb and sucks, I simply agree it could be better. I'd take it over Junction, Sphere Grid, Crystarium, or FFII's system. I actually prefer it over Materia as well.
Except you can by end game and you keep forgetting that teaching magic is not the only system in VI. You still have stat boost and relics to contend with and in the regard VII is even more liberal since you can just keep making stuff like Double Cut and W-Magic materia for your party whereas in VI, there is only one Offering/Master's Scroll and one Gem Box/Soul of Thamasa so overall you're more restricted in abilities in VI than VII is especially since Master Materia will get you more than just teaching every spell and free up most of your slots for other things. Likewise farming stat boosts allow the user to max out most of your parties stats wheres as in VI you only have as many chances as you have from your current level until Lv. 99, making it far more limited especially since the best stat boosts don't appear until the second half of the game.It's not weak because of my compulsion (I don't have a compulsion to grind abilities for everyone anyway) it's weak because it gives everything and demands nearly nothing (besides grinding, which only takes up player time and leaves no mark on the actual game itself besides making characters better in small increments as a side-effect).
Giving all your characters the same abilities in VII is the player's choice, but they can't give everyone everything, which is what you can do in VI and which begins to happen naturally over the course of the game.
So by end game in VI, I'm still differentiating my party through the use of limited relics and limited high end equipment that alter skills, defenses and strengths of my party. Whereas in VII, I can have a party that has all the same skills, magics, summons, stats, can all do max damage with ultimate weapons, and the only thing to distinguish them is armor, and use of support and independent materia but considering there is little value in giving characters different attributes with these cause if a combo is good and VII allows me to get all the materia I need for it at no cost except my time, then I don't see why I should bother. Did I mention Master Materia is at no cost except my time?
You know what's really funny about this? I've never done that, I always make my characters learn every spell on a Esper before switching out but largely cause I wanted them to bring something to the team, so again I would argue that you the player is making this worse for yourself cause I never really dealt with going to the Opera with everyone at least knowing Bolt. I chose to instead let the espers develop who my characters were in the party so I had two status units, one heavy offense, and one dedicated healer. This isn't about bad design, it's about choice. In VII I could make one character a healer, another a mage, and the last a fighter or I could make them all into Red Mages, it's not bad design, it's player choice. Also not teaching characters magic in VI is akin to not giving Green materia to characters in VII, it limits the characters role but it's not weakening them. The issue here is that in VI the choice has long term consequences because you choices are often permanent whereas in VII it's far more forgiving and mostly transient.Fine, as you leave Zozo and head to Jidoor.
Anyway - the first Esper you get is Ramuh. The easiest spell to learn from Ramuh is learned at a clip of 10x. Say you learn 2 ABP per fight walking on the World Map. In 5 fights Locke will learn Thunder. In 5 more, Celes can learn it. 5 more, Cyan, etc. Yes, different things are learned at different rates, but the natural progression of the game let the members of your team learn the lion's share of what the Espers have to offer. I'd call this liberal. Not having at least two characters learn Thunder by around the time you set foot back in Jidoor I'd call neglect. What I wouldn't call it is customization.
Except you're wrong, because you're forgetting how linear progression works here so it's not like VI hands you all the best espers from the get go, and relics are also handed to you in a progressive manner that prevents you from customizing your characters exactly, besides teaching magic is not the whole system. Relics and stat boost play just as much of a part and so does equipment, likewise, I could still be going into the North Crater with my party being able to use all the summons and use every command ability(I could even have a Master Magic as well since all I need are command materai and KoToR to beat Ruby) but W-Magic which in my mind is not different from every character knowing every spell in VI at Kefka's tower and in both scenarios at no cost but my time.In VI (I'm going to make one last comparison to VII, and not a value judgment of VII), every character's gateway to knowing everything is barred by grinding. Do the grinding (which isn't even that demanding), and you know everything. In VII, the gateway to knowing everything is... the game itself. As in, you literally cannot give someone every ability at once (barring the endgame secret Materias). It doesn't matter that Deathblow sucks or whatever is garbage, this argument is about what the game does and does not allow the player to do with/to his party over the course of the game.
Here's the thing about VI's system and why it's not weak and why it's a multiple of systems. In VII, I can't make a real mage, I can make my character mage centric but I can't make an honest to goodness FFV style mage except with Aerith and even then I can't get her access to the best command skills and support materia to make this work. I have to overload my character with end game magic materia just to get their stats fixed, I'd need a Master Magic materia, but all the end game gear is shared except for a few pieces and it's all powerful armor so I'm much beefier than a real mage, likewise, an ultimate weapon will allow said mage character to stay as a high powered Red Mage that can do high physical damage which no red mage could really do, let's also not forget Limit Breaks can't be changed or removed so eventually Cloud's going to pull off Omnislash and with his Ultimate weapon it will be better than anything he can do as a mage. I could give them a weaker weapon but as you've clearly stated that's weakening the character not to mention the lack of slots would prevent my Mage from doing as much. In essence unless you limit your characters in VII all you have at any given time is a party of jack-of-all-trades.
In VI, I can take Cyan, I can teach him every mage spell, level him with Valigarmande (+2 magic) for several levels to make his magic as strong as Terra or Relm, equip him with a Merit Award relic which would allow me to fully equip Cyan into mage-centric robes and Rods to boost his magic potential and negate his ability to use Bushido and I have now transformed him into a bonafide mage and likewise I could boost Relm's strength with Gilgamesh (+2 Strength), slap a Merit Award on her and transform her into a sword wielding knight decked out in full Genji Gear.
The difference between these two scenarios is that in VI, my choices do in fact have consequences, I have limited stats raising capabilities, and I have actual one of kind skills like Dual Cast and Quad Slash that have to be mediated to the best candidate. If I don't teach Cyan magic, he isn't gimped, cause teaching magic isn't the only form of customization so it's not the same as saying you're not using materia in VII, or not using Junctions in VIII instead it's choosing not to use Magic Materia or not using the Magic command because I have other customization options. Not teaching Cyan magic but focusing on using Relics and stats boosts to build him into a speedier and hard hitting fighter while also gaining his Bushido skills is the same as restricting Cloud from using Magic Materia so I can use the slots to give him command materia and independent materia to raise his stats and abilities.
VI's customization is built on four pillars of options: Character Class, Magic, Stats, and Relics. With Character class, I have a multitude of characters with unique skills and playstyles so party dynamics is one element of how you build a party, I can teach characters magic and only one character is actually restricted. I can raise the characters stats and choose to either strengthen their talents or raise opposing stats to make them more diverse. Finally I have relics which give my characters unique abilities and defenses that are not covered by the other three. Unlike other systems except FFII, FFX, and post-FFX entries, I actually have multiple customization systems that work together so choosing not to let one character (who doesn't need it) to by pass one system in favor of the other three is not the same as neglecting the whole system, it's the same as ignoring the options in other systems like neglecting to use magic materia or the Magic command in VII and VIII respectively. If you feel that not using one system is weakening them, then as I said before, it's in your head if you thinks its making them better to have it. Teaching Cyan magic and then turning around and making him use his Bushido command or simply never using him again after is simply you wasting your time. If you do let him use magic then you made him more diverse by allowing him to weakly use magic and this in turn opens up more customization decisions because now you have to decide to improve his strengths and make him more specialized, or choose to make his new found diversity into his strength by raising the areas where's he's weak. See, I've just shown you how the choices you make lead to other choices and how the systems all work in harmony with each other. Each one leads into the other cause a decision in one can change what you do in another. If you teach everyone magic, the only strength you get is that you open the plausibility of using the limited magic enhancing Relics for most of your party but you'll eventually choose to go with one group, at worst, you simply wasted hours of your life to fill up a stat sheet, and it's not like I can't have similar experiences like this in almost every other FF game, so it's not like this is somehow a unique fault to VI.
I agree that the unrestricted magic learning system could have been better implemented, but trying to prove this by comparing it to a system made years later on a more powerful system really doesn't prove anything cause you're arguing in hindsight and not historical context, I can argue that VI's customization is better than FFII and IV's but that's just not a fair comparison cause VI was made years later and learned from its predecessors. My main point is that when you take in account every aspect of VI's customization options, it was pretty amazing at the time, and it still holds up better than some systems. Is it flawed? Hell yeah but what system isn't? Answer = FFV Job Class System