I played Okami on the PS2 and I swear, I was absolutely absorbed. It's a fantastic adventure, chock full of engaging sidequests, innovative and gorgeous graphics, and an excellent control system. However, this all means nothing. It will assuredly not appear in Smash Bros., guranteed. Okami is a claimed property, origonally owned by Clover Studios (a small, yet very talented branch of Capcom) until it was axed, and was snatched up by a secondary propriotor. This essentially makes it practically a 4th party character.
Even more so, Okami has absolutely no history with Nintendo at this point, despite the port appearing in 2008, as it still doesn't exist yet. Not only that, but it has no real roots in the Gaming realm. Look at the roster of characters and you'll notice that almost all of them found their beginnings in the 90's. As such, it's hard to believe that a character born in 2006/2007 has much of a chance.
Don't get me wrong, Ameterasu (Okami) would make a choice applicant in Brawl, but I'd like to see a few more sequels and a bit more fan-love before I'm going to allow it.
EDIT: For the record, the character's name is actually Ameterasu (sometimes called Ammy). Okami is the title of the game. The mistake you're presently making is akin to referring to Samus by the name Metroid.