look i can't remember every single detail (might replay it soon to refresh my memory) but to me the overall plot was neat and made sense, i liked the party, pulse (cocoon part could have been better), gameplay, soundtrack had also nice tracks (for ex: oerba and sunleth waterscape), and wasn't bothered by ff13 liniarity. if you dig deep enough you might find some inconsistencies in the story but, at least to me, not big enough ones to kill my experiance. so let's leave it there.
The reason you don't remember "every single detail" is because important stuff was never actually told. This is why Final Fantasy XIII has terrible story telling. You probably didn't even know Fang destroyed Oerba since the part of Cocoon she broke fell onto the village. Important stuff like that is all in the datalogs and they shouldn't be. Gameplay wasn't bad, they just didn't balance the game. You'd spend atleast half hours at a time over powered and just button mashing X until the next boss, that's a long time. Hell, there's 6 hours of cutscenes in the game divided up into 40 hours of gameplay; that's 50 minutes of button mashing for every 10 minutes of cutscenes. That's not even taking into consideration some of the longer cutscenes which puts the grinds even longer.
To say the truth; the story is fantastic, the problem isn't the story the problem is how they told it... or rather the lack of telling. Everything I said above is the reason the majority of the people were put off from the game. It being linear wasn't even the problem; them making a 15 hour linear game and stretching it over 40 was the problem.