After reading all of Cybertron Reloaded, I found myself looking at Collision Courses, and was kind of disturbed to notice that apparently, Onslaught had joined the Impericons.
The thing is, I found myself quite liking UF-Onslaught in CR so far. He's smart, on-the-ball, interesting, and rather content to be a second-in-command, without any of the major hang-ups of previous Decepticon second-in-commands *coughStarscreamcoughCyclonuscough*. The only reason I could see for him to join the Impericons is for love of planning battles, and there's still plenty of battles for him to fight on the Decepticon side.
What I'm saying is that the Impericons are uncouth rascals without old Megatron's sense of style, or even Galvatron's interesting insanity, and Onslaught is much better than they are. I feel he deserves a spot at Thundercracker's side.
Off-topic, has there been much faction-swapping between the Autobots and the Decepticons, now that they're no longer two warring groups but instead two halves of the administration of Cybertron? And have many neutrals who didn't want to fight their own kind, but are willing to fight for their world, joined either group?