I haven't played as everyone yet either but I can say that Terra got nerfed pretty bad so far. I may need to just spend some more time with her but its really obvious somethings have been changed.

Holy and Blizzara have both had their range cut almost in half and Holy especially is much slower than it used to be even in EX-Mode making it ridiculously easy to dodge or block. They both have lost a good bit of their accuracy as well it seems. Also, she can now move when using the Flare branching attack. Fire is faster but much more noticeable and of course has her new Firaga branching attack. Meltdown's second variation has much better tracking and can turn a bit easier making it a bit more difficult to dodge. Tornado has a much slower start up time but its range has been improved. Her movement speed seems a bit better but she's still incredibly slow to recover from using a move meaning she's still a sitting duck at close range.

With her best attribute gone (her incredible range), several of her moves made easier to dodge or block, as well as the usual weaknesses of magic such as being able to simply dash through it and reflect it back at her (which always crits since its treated as a counterattack); I can't say I'm thrilled with my poor Terra's changes cause she's really lost most of her strengths with little to show for it. Considering guys like Golbez and Cloud got very minor nerfs and people like WoL, Firion, and Kuja got major upgrades,

I'm kind of sad that she may have lost her competitive edge. Kefka is a much better character compared to her cause at least his moves got sped up and are close to mid-range, meaning he can deal with opponents better but Terra's only close range game has been nerfed and she lost her long range game, meaning she's trapped at mid-range where guys like Cloud, Bartz, Kain, and Golbez simply have to mash O to attack through all her spells and reflect them back at her while nailing her with their own attacks. It looks like Terra will have to be played very defensively...