That's an interesting comment, given that my first impression of WoW is that it's just like every other MMORPG out there...except for CoH. Admittedly, WoW uses the old cliches better and more fluidly than I've ever seen, but they're still cliches and they still borrowed the majority of their game mechanics from other games. WoW is an improvement; CoH is an innovation.
You're right about the equipment thing--CoH has none, so sidekicking works really well, but I can't think of how they could do sidekicking in a game heavily based on equipment the way WoW is. That's a very good point that I hadn't thought of. You're other concern, about instanced missions and quest-based experience, isn't a problem--CoH is chock full of instanced missions and quest-based experience, and sidekicking works fine (the trick, you see, is that sidekicking changes your effective level, so if you try to complete a level 10 quest while sidekicked up to level 20, you won't get any experience at all).