This was a game that truly rewarded those that explored the world. Hell, about half of the MASSIVE areas in the game are optional... and you wouldnt notice if you were just shown them. All the areas in this game are fully fleshed out, unique, and very memorable.
The skycity of Bhujerba, dalmasca, Nabreus Deadlands, the Pharos... ahhh need I go on.
The license system, though hated by many, is loved by me. It allows for SO MUCH customization, and if you're creative can allow for some extremely unique challenging and interesting runs.

Hell, even the bestiary is AMAZING. So much lore and history to read about. It's glorious.
This game never actually had to grow on me, I loved it from the start. I never understood the story as a kid, but I adore it now. I love me the political story FFXII wove, and all of the characters were beautifully written. Also, this games Cid kicks ass.

It definitely had flaws though. Late game magic broke the ATB gauge and as such became horrendously useless... and the story was SO easy to forget because of the pacing. Though I'm not sure how they'd keep a story alive in such a HUGE world full of side-quests and optional content. Also, many of the character designs were either impractical, silly, or overly sexualized. It always bothered me, but at least it was never was truly able to draw me out of the world.

It's easily the FF I invested the most time on, and definitely my favorite.
Is it a perfect game? Hell no, but it comes pretty close.
It's a very love-or-hate game, but if you give it time it may very well grow on you.