Recent scans have shown that Phoenix Wright (Ace Attorney) and Ingrid (Capcom Fighting Evolution) where considered for the Tatsunoko Vs Capcom, but didn't quite make it through. Dissapointed fans should keep their hopes up however as an interview with Ryota Niitsuma, the producer of Tatsunoko Vs Capcom, has suggested that the characters may still make it through via DLC, but it will be in part up to Nintendo.
Since the solution to the Wii's storage problem with the added SD card compatibility, a couple of developers have applied DLC for games on the Wii. Most noticeably seen on Guitar Hero with players being able to download extra tracks to expand the longevity of the game, other titles on the Wii lack the ability to expand once released. All companies that want to get DLC for their games have to go through Nintendo, and with the few games that actually have succeeded, they may be a tough nut to crack on the subject. Hopefully, with the large amount of popularity surrounding Tatsunoko Vs Capcom, especially within the hardcore gaming community, Nintendo will give the go-ahead for DLC