That would be great!
I mean, I'm by no means a fan of the UU, but I really enjoyed the crossover.
I hope for more crossovers that not only concern Spidey, for example a crossover of the X-Men-Teams, and a meeting of the Avengers and the Ultimates.
How Marvel Time killed the MU
Marvel Now! has been Marvel testing the waters for a reboot. I bet "Spider-men 2" will be the catalyst for the Regular Marvel U. and the Ultimate Marvel U. merging and reshaping reality and rebooting continuity. Other than that, I can see no reason to do it. Oh, except $$$. The first one wasn't that good and mixing the two universes (something I always thought they said they wouldn't do) only diminishes the Ultimate U. in the long run.