I have yet to play WKC. Is it like Final Fantasy XII? It's quite possibly my favorite FF thanks to the amount of freedom and versatility you have.
Kind of. I don't think it is quite as good as FFXII to be honest. There was a lot more you could do with the AI in that game with the gambit system. I do think you'll find it's a game with a similar combat system just not executed as well.
That said if you like JRPG's and have a moderate tolerance for cliched story lines with groan-worthy dialogue at times, you'll probably enjoy it. I think the largest complaint with this game, at least the single player part, is that with all of the abilities you can unlock, there isn't a need for many of them. You could easily just spam basic attacks and win any battle. The graphics, environments and music are great and there are tons of things to do in just single player.
I don't have much experience with multiplayer, but what I have played of it is quite fun, especially with a good group of people with mics.