I had no problems with the world itself. Seemed like a well enough constructed world. I have FFT: War of the Lions, which I haven't played yet, and I intend to play Vagrant Story at some point in the future.

XIII battle system is mostly picking the right combo of classes and mashing the "Auto" button, then changing classes and doing it again.
As for grinding, the first 6 or 7 chapters of the game are so linear, you can tell when a boss will arrive by just looking at how many more skill points you need to completely activate the available skill tree. Then, many hours in, the game sort of opens up and throws you into a wasteland scattered with mobs you can kill, and mobs that can kill you. You're supposed to figure out which is which on your own.
And don't get me started on the story, written in the marvellous "making stuff up as they go" style.

Yeah, Basch was going to be the main character. Vaan being shoehorned kind of works though, since he is literally irrelevant to the plot, and is just there for the ride.
Hell, the other characters mock him and he doesn't advance or move anything plotwise after getting the full party, he just follows.

I thought Final Fantasy XII was fun, the combat required a lot of grinding though. I never finished Final Fantasy XII or the other Final Fantasy game I have, which is X. I got pretty far into FFX but I'm not sure how far I was into finishing FFXII.

The reason I quit playing was that I got a new Xbox 360 for Christmas 2011 and no longer had much desire to play my PS2 after that. Then a few months later in May 2012 I got the laptop I'm using now so I could access my GOG games and get more GOGs so I no longer played my 360 much after that.

I couldn't get into the combat. I played it when I was 12 or so, when I started knowing enough english to appreciate RPGs and other story heavy games, and I was indeed enjoying the story up until I stopped (which was not long after they left the first city, so I was in the beginning).

I just was never very interested in micromanaging my party and couldn't understand the point of being able to move in real time in combat. I attacked, then had to wait till my regular attack was available again, in the mean time moving was useless, I tried escaping from the enemy's attack but that just meant they were able to hit me in the back. It felt more productive to just stand still the whole time because if they hit me in the front at least I'd get some chance to block them.

Have you ever played Rogue Galaxy? That game kinda reminded me of FF-XII in its level up and combat systems, but there were some crucial changes. Combat was in real time and you had an "action bar" that once depleted you had to wait for it fill back up again, like in FF-XII, but here the bar allowed you to attack multiple times before it was completely depleted, and even then you were able to manually block which, if successful, would intantly replenish the action bar. It just felt a lot more involving.

Can't speak for others obviously, but I didn't care for it for a few reasons.

For one, the combat felt like something out of an MMO to me. What little there was that couldn't be left to the gambit system, anyway. I've almost never been able to get into those kinds of games to begin with, without someone dragging me along.

Another thing was the story, I just couldn't get that interested in it. Whenever I stop mid-game and wonder "Why am I doing this crap again?", it's clear something's off.

The thing that annoyed me about it most though, were the characters. Probably for a different reason than most, but I get irked by odd things sometimes. While some of the personalities and such were rather shoddy, what really frustrated me was that the end party consisted of six Humes and a Veira. Why even set it in a FFTA-style Ivalice if you're not going to at least give the option for some racial variety?

There are other issues I had with it, but those are just the first three that came to mind.

Another minor quibble I had was the requirements for finding some of the unique weapons (like the Zodiac spear) were entirely ridiculous and impossible to figure out without a guide.

Personally, I loved the combat system. Managing the gambits to make a good preparation and then see how you fared against the enemy was fun, and I've grown to be annoyed with those sudden encounters (they really irked me while playing Evoland, I was actually suprised at how much they annoyed me while I used to enjoy that).

There also were a lot of side missions and stuff to do beyond the main quest, which is great by my book. I can then choose to do them or not, it puts it way ahead of FF XIII's corridor.

This said, I found the story absolutely disappointing, and I play(ed) FFs for the plot. In almost all FFs, the story gets a seemingly normal guy who gets deeper and deeper into whatever is happening, only to at some point get a revelation that completely twists the situation around. In a way, it's like a James Bond movie: you know the trail the story is going to take, but you don't know how it's going to take it, and that discovery is fun.

*possible spoilers ahead*
FF XII puts you in a story of a dethroned princess, who fights against the empire who conquered her nation. And... that's it. No twist, no surprise, no nothing. And the story of this princess isn't that interesting to begin with, but as Elmofongo
Elmofongo said to each their own, that's a matter of taste. What is not a matter of taste is the lack of intrigue and twists, and the absolute disappointment of not ever having the world open to you like on previous iterations. Hell, there's this major country opposing the empire, and you never get to see it!

Finally, I can hardly remember the characters, which is a clear sign of their lack of appeal (to me). The sky pirate dude was kinda funny, but that's it, the rest had no impact at all. They were just there.

I like to say that FF XII and XIII together make just one FF game. XII has a lot of exploration and variation, plus a fun combat system; while XIII has a storyline focus, even if I don't care about it, and strong(er) characters but limits you to a inescapable corridor.

Are the requirements easily missable (I mean as in if you miss the opportunity it's gone forever unless you start the game over).

For the Zodiac spear, you have to get certain barrels in a certain order and not touch others, so yeah its totally missable. Another one the assassins dagger you had to do something special to make a certain monster appear and then... do that and beat it 256 times. And there is nowhere in the game that explains how to do these things. I found those requirements just unreasonable and ridiculous.

I honestly don't remember much, it's been awhile since I've played it.

I personally loved the combat for the most part, it was in my opinion the best part of the game. The license board was a welcoming change and was more expansive than 10's sphere grid. There was plenty of exploring to do and actual side quests to take part in (even at the beginning of the game). The story and characters...I really don't remember anything aside from not caring about anything that was going on.

After playing 13 and getting to a certain point, I kind of felt bad for giving 12 a bad vibe. At least 12 had actual exploration and everything else that made it a legitimate Final Fantasy game. 13 on the other hand...it was all in all a half-assed version of 10 but with no understanding of basic exposition and a confusing story (with cliff notes to explain shit).

Personally I hate 13's world worse than 7,8, and 10 heck I take it back 7 and 10 were OK, but I hated 13s world more than 8.

I hate this future techno world that does not make sense, its just too alien for me in a bad way, I feel the same for Final Fantasy Versus 13 (which is now going to be considered 15) Type-0, etc.

Could also be related to the art-style. I'll be the first one to admit I absolutely hate Shin Megami's art style

or the fact that the main series takes place in a school.

I do however like Shin Megami Tensei: Lucifer's call, though still not a fan of the art style

As a guy who is not a big fan of the Final Fantasy series, (I seem to be the only one who goes nuts over the first game, NES difficulty and all.) I think people hate it because it is a little too different, at least that is what I hear seeing that I haven't tried the game yet.

The remake on GBA, PSP, and iOS are much easier now, since you can save anywhere you want plus other minor things.