I'm not sure if this means that any chance of a MvC4 happening is dead, but if it were to happen, there'd have to be a canonical reason for the two universes to meet in terms of the MGU (Marvel Game Universe). Not to mention pinning a place in the timeline for the merging of the two worlds. This could also potentially limit the roster further than it already was in UMvC3 (Marvel chose the characters for their side of the roster for UMvC3, sans Shuma & Sentinel), depending on if anyone dies, retires, or has yet to become a hero/villain before the events of MvC4 on Marvel's side of the timeline.
If MvC4 happens, a ton of work will be put in the story of it, or at least its existence in the MGU.
On top of this, I anticipate that the MGU will be heavily inspired by the MCU. Basically, expect more emphasis on the Avengers & the Guardians of the Galaxy like Marvel's been doing recently.