That's actually one thing I'm curious about. With GTA V (and of course inFamous as well if we are talking open-world) they focused on two consoles only, so the team wasn't as "stretched" in a sense. With Ubisoft and Watch Dogs, we've got five console platforms - each of which has varying specs and three of them are rather "old" in tech sense - and the PC platform which fluctuates depending on user specs.
Taking this into account, it definitely seems like the focus was pushed to new-gen/PC what with the E3 2012 demo focusing on what "could be next-gen" at the time, and now seeing the 360/PS3 versions. At the very least though, the past-gen versions weren't "phoned in" like we've seen with Titanfall, but it does make me wonder whether there was any point to continuing development on X360/PS3. I guess Ubisoft, like other publishers, were caught out by how quick new-gen uptake was and had figured it would be worthwhile.