I wouldn't say the matches are shorter necessarily. I've only done two, and yes, I am still getting used to the gameplay. It's way to early to make any kind of judgments yet.
As far as rivalries and allies, they seem to be slow in forming or dissolving in Universe. Cena and Ryder formed a tag team, but that's the only one I've seen so far in the first year of simming.
I have noticed rivals coming down to interfere in matches, though, and allies coming to my aid, so that's cool. But usually the guy just runs down and stops before actually getting involved in the match. I've seen a couple instances of guys distracting the ref during a count.