I've decided to give Final Fantasy XIII another try, after almost 3 years of cooling down from my initial disappointment.
It's not bad. I kinda like it. Not the best Final Fantasy ever, but it's at least 5x better than VIII.
I like the premise, I like the setting and enviromnents. I like the combat, even though it's the source of some of my disappointment on account of it being, in some ways, a dumbed-down version of XII's combat, which I loved.
The main problems with the game are the fact that most of the main characters are annoying as hell, and how slowly the game's mechanics open up... especially painful when coupled with how linear it is. Also annoying is how frequently you jump between different characters in the game, at least the early chapters. Especially since that means you're constantly jumping from characters that you find tolerable to characters that you can't stand, often after only getting to play as the characters you like for maybe a handful of minutes.
The combat, as I said, is basically a watered down version of XII with a few so-so elements thrown into the mix. Which means it's good, but not great. Combat no longer takes place on the field (disappointing, but understandable given the corridor-like design of most of the environments), and fully customizable gambits and fully commandable party members gets droped in favor of 6 basic paradigm roles and only the leader being directly commandable.
So overall, meh. I moderately enjoy it, but it is rather disappointing as the final main entry in the series before it jumps ship from turn-based altogether in favor of an action-oriented approach with XV.