Ubisoft needs to do like EA and come up with a single big engine for all their franchises. As it stands right now they’re using a different engine for each franchise (Anvil for AC, Dunia for Far Cry, UE for Splinter Cell, Watch_Dogs is also using a brand new engine) and I bet that’s gotta be a support and technical nightmare.
I don’t know how flexible the Watch_Dogs engine is, but since it’s built from scratch for next-gen and has PC support from the get go, I’d guess that would be a good choice for an universal Ubisoft engine.