Well that is actually a pretty common viewpoint on trading guys like Kesler. You don't typically look towards a lateral move, at least it doesn't seem like most GMs or analysts do.
Trade doesn't necessarily equal rebuild and there are certainly past moves that have proved that. My point was and is still really simple...if you trade Kesler you probably need to replace his offensive output or you are looking at another year of watching the Canucks struggle to score goals...possibly even worse than last year.
So why trade Kesler, a good player, for an equally good player? I suggest you trade him to get better in the future, or you package him for a guy like Weber to get better now. But again, you make a deal like that, which I would love, you have a hole on offense you have to fill which is not just going to magically come from somewhere else.
I'm definitely agreeing with a lot of what you are saying, just not necessarily the basis from which it is founded upon.