All I can say is WOW. They seemed to have made some changes to this game, definitely for the better it looks. Here we go:

4 new playable characters.Zankuro, Amakusa, Gaoh, and MIZUKI The old poppy code no longer works, but I'm bettin the Woof-Kitty is still playable.

Mina gained a command throw, probably to help with her abysmal close range game.

Hanzo/Galford's SPD got beefed up with some good range.

Rera's moves have been slowed down.

Kusaregedo's moves were slowed down for whatever reason, most notably his C moves. Command grab is still a pain to get off.

Yoshitora was toned down considerably. His moves are slower in general, and not quite as good (although his super is still quick to recover). In general though, nothing does as much damage as it did in 5, for every character.

On enlightenment mode, the guage now only extends as far as halfway through your life bar, and once you do go into enlightenment(with BCD, instead of the SS5 motion), the meter runs out alot faster. Ouch. For a subsystem that wasn't really that bad, it got hoed.

When you do a rage explosion, there's a new move you can do.

Aesthetically the game is much improved. Several new stages (notably the boss stages from other SS's, although there's more), the bars and meters and what not all look much nicer, there's a new character select screen, and new character artwork. You can see the select screen here http://www.t3.rim.or.jp/~y-ukon/ss9/index.html. In general I've heard the game just looks "cleaner", and to be honest, from the screens I saw, most people were mistaking this for an atomiswave game