Well apparently there aren't as many zombies because thats what Capcom wanted and not because of hardware limitations, they also made the zombies to be faster and more agile the the original. Games on PS2/GC have proven you can get a shit load of enemies on screen so I believe Capcom in a way.
There seems to be enough for mindless hacking and slashing, should be decent as long though nothing special as you forget about the 360 version. To be honest, if this was the first game in the series people would be more hyped.
Trailer makes it look like a fun free roaming, just something you can waste time on.