Capcom veteran and long-time Street Fighter producer Yoshinori Ono has told Gematsu that there will be no boxed versions of any future Street Fighter X Tekken updates: "I would say that you don't really need to worry about a new version of the game coming out. If we choose to update the game, it will be done in the same fashion as Street Fighter IV: Arcade Edition."
"The same fashion," as you'll recall, involves releasing an updated version of the game as DLC rather than at retail, and for a discounted price. It sounds great, and we certainly hope Capcom goes that route from now on, but Ultimate Marvel vs. Capcom 3's existence isn't the most reassuring thing.
Ono also said that Street Fighter X Tekken will make use of brand-new netcode, rather than the code used in SSF4:AE or UMvC3. He didn't go into specifics as to what differences or improvements they're hoping to make, but decreasing latency and improving match-up algorithms usually take front and center when improving netcode.
We're optimistic that Ono's words will ring true, but we also know that we can't always get what we want.