To throw in my own ideas.

FFVI - The first game that really challenged my preconceived notions of interactive narrative. I'm not a big fan of conversation trees and they tend to pull me out of the narrative, which is why Mass Effect and other Bioware titles don't usually rank high for me in this department as they always feel so artificial to me. VI did a few tricks with this that really surprised me like the Opera sequence and rewarding exploring by having tiny bits of narrative to find. Granted, Chrono Trigger took this idea so much further with the Millennial Fair/Trial sequence, but it really began here with VI catching me flat footed when I discovered that I was actually going to have to participate in the opera instead of being a passive viewer. I feel immersion works better when it's little things and more subtle than just opening up a dialogue box asking you what to do.

Dark Souls/Symphony of the Night - I have a tough time considering SotN as an RPG but I can't really fault the logic of why people think it is one. Instead I'll say Dark Souls since it pulled the same stunt. These games pretty much solidified how I feel open world design should really work. It's not about a giant sandbox map with the ability to go wherever and farm samey quests. Instead these games have carefully (well mostly) designed maps that are interconnected to make it feel really cool when you've been progressing through some challenging places only to find your way back to one of the earlier stages. I love that interconnected feel and I appreciate that the level design has purpose that still emphasizes exploration without feeling aimless.

Disgaea - This game completely destroyed my thoughts on grinding and power levels. In many ways, it did to RPGs for me, what Austen Powers did to James Bond in general. Parodied it's biggest cliches to the point of absurdity that made going back to the serious source materials unbearable and silly in practice. I don't really grind anymore in games unless it's for rare drops and even that is something I have a very defined threshold for. This also kind of destroyed over-the-top visual antics for me as well. Characters doing improbably sword works on forty foot tall monsters doing a quadrillion damage just feels silly to me instead of awesome.

Shin Megami Tensei III: Nocturne - The game that introduced me to the Press Turn System. In truth the Press Turn system became the golden standard for me when it comes to what I really want out of a combat mechanic. It's fair minus a MC Death = Game Over shenanigans. What I mean is that the mechanics works both ways. Most RPGs have the player characters and enemy characters work on different rules with the enemy usually having a numbers advantage, but the player having a statistical or gameplay advantage. Press Turn works the same regardless of whether you're the player, a regular enemy, a boss, or even a secret boss. The more interesting element of it that I just don;t see in standard RPGs at all is that the Press Turn system offers a defensive game. In fact, most games that feature the true Press Turn mechanics eventually evolve from an offensive game to a purely defensive one. So In stead of trying to increase your number of turns, you build parties that specifically reduce the enemies instead. Can't really name too many games that have such a neat element to it except maybe Bravely Default. The final element I love about it is that the rules are actually really simple. Exploit an enemy weakness or land a critical hit, and you gain a turn. If the enemy resists an attack you lose a turn, and you lose all of your turns if they absorb, void, or reflect your attack. You can have a maximum of eight turns in normal play. After Nocturne, it's strange going into other RPGs that have more elaborate rules and combat systems that don't feel satisfying with the extra elements.

Chrono Trigger - In terms of overall design, I feel Chrono Trigger is actually a perfect game for the most part. That's not to say its design is everyone's cup of tea, and you're more than welcome to dislike CT's game design if it doesn't fulfill some niche you love, but from a designers point of view, I feel CT is executed well. It has a strong pace, a serviceable battle system that promotes variety and experimentation from the player, an excellent leveling curve that will deter most first time players from grinding, possibly the best collection of side content in any RPG, the game introduces several new elements and mini-games seamlessly into the narrative throughout the game, and it has excellent replay value. Best of all is the game's overall ratio for these elements which give you just enough content to keep you satisfied, but never overstays it's welcome either. CT really exemplifies a less is more approach about content because I still find the game to be one of the most satisfying to complete despite most of its extra content being easily completed in a few hours as opposed to most games trying to stretch their games by more than ten hours with samey bulltrout.