I've always thought of it this way: Cameron, realising he cannot beat Revok, sets himself on fire, and then swaps his own mind with Revok, thus dooming him to die in Cameron's body. A kind of 'back-door' trick if you will.
I think so, more or less. I would argue that Vale was at least as strong as Revok but perhaps he didn't think he was, or just felt it was easier to trap Revok than take him head on, as it were.
My interpretation: they were equally powerful, but Vale didn't have Revok's complete lack of regard for the minds and bodies of his victims -- so when it came down to it, Vale actually couldn't bring himself to destroy Revok. It was Revok who directly, or as a result of their interaction during the struggle, set Vale on fire. Then Vale's only option for survival became to merge with Revok in Revok's body. "We've won."
I also think they were on par with each other except Cameron was less experienced with his powers and was not as used as Revok was. And because of this he was unpredictable and was imaginative in using it. Unlike Revok who probably developed his powers in a straightforward manner.