Well, its disappointing since there was a clear character progression from Alien Force to Ultimate Alien. Besides, his most distinct features in Omniverse, his constantly saying how he saved the universe and trying to go at it alone, were things everyone kept calling him out on in the previous shows.
I'll be honest. I never really did like Ben in Ultimate Alien. Things went his way a little too often and near the end was basically Ben being awesome and his entire supporting cast reduced to taking on mooks.
He still has the "I'm the amazing Ben 10" attitude in Omniverse but everyone calls him out on it here. His supporting cast is useful now and can actually handle themselves without Ben needing to be there to save the day. All in all I like it much better.