Combat for me was actually the best part of the game. Though as stated above, it has it's problems. I felt my biggest issues with combat was that:

a) it didn't turn out to be as expansive as I thought it would be. In the end it's pretty simple and doesn't have as much weight as other entries but this can be a good thing for some people. What I mean by this, is despite letting you input some commands, if you are not playing something like Ravager or Synergist, you won't be doing much. Many of the roles really don't have complex move sets and often times I found myself saving time by hitting auto battle cause mashing X got too tedious for me.

b) I often found myself feeling I could make better versions of all the paradigm roles with XII's combat system. The A.I. is competent but not by much. All of the mage type roles have some annoying A.I. glitches that will become more apparent as you get to later parts of the game. From healing prioritizing over removing more harmful status effects, Synergist have a hierarchy of priority with the buffs they cast which oftn means if you need just Haste/Protect/Bravery on a character, you have to wait until Veil, Shell, and Faith are added as well, wasting time. Even worse is when the enemy can remove buffs, the Synergist will keep wasting time trying to add back buffs to the one who has been dispelled instead of just trying to get the full set up on everyone else, this gets really annoying with a Sentinel set-up.

Sentinels are extremely useful unless your enemy has AoE abilities. Having them there, raises the parties defense but since the A.I. loves sticking close together, often times, the Sentinel ends up drawing more damage to fragile party members cause the player can't directly control the Sentinels movement. This is especially annoying against a specific boss called Barthandelus who uses chain cast spells yet the room is so large that many of these spells only hit a certain area and could actually be avoided if the Sentinel could actually be moved away from the rest of the party.

It's competent but it's hardly efficient. The other downside comes from the equip/weapon system which takes forever to unlock, and is terribly time consuming and requires ample amounts of time for farming for specific materials. You win items off monsters that can be fed to the weapons and accessories to raise their levels and their abilities. Once they max out, some of them (all weapons actually) can be given a special rare item to transform them into a more powerful item but its level is partially reset yet at the same time the new levels will make it stronger as you level it.

The problem is, despite the whole XP bonus system that organic items give to items, the amount of items that give substantial XP are very few and incredibly rare from treasures and monster drops. Even with a 3x bonus, most of the games items will barely give you 100xp and even those items will be few since monsters and treasure rarely give you more than 2 or 7 of them at a time. Luckily there are shops you can purchase the best XP giving items but they are terribly expensive. Monsters don't drop gil, you have to sell the items you feed your weapons to get gil and much like XP they give terrible small amounts of gil, so then you need to farm monsters for one of the rare items that's only purpose is to be sold for gil... So no matter what, expect to be farming a lot in the final chapters.

I still consider this to be less annoying than the main cast and storyline, which had a lot of potential but falls short on so many levels.