Some people on SRK are bitching about Arakune and saying he's overpowered (this isn't a question of whether he's OP or not, I don't really know. Not enough experience or skill to really judge):
http://forums.shoryuken.com/showpost.php?p=7102839&postcount=211
I know of one of his unblockables (http://www.youtube.com/watch?v=-IOZE9niikE) but it's plural, so what are his other ones?
Also, apparently he has guaranteed guard break strings, and mixups you 'can't react to'. Can anyone here confirm this, or is he just talking out of his ass?
These things are probably pretty advanced (if they in fact exist) and it'll be awhile until I can do them, let alone incorporate them into my game, but it's still good to know.