Aside from random periods of injury, I think Edge has done extremely well in and for WWE. He's not too egotistical to have a problem with putting someone over and make them look good while doing it - you can't say that for a lot of the top guys. His abilty to sell is not restricted to in-ring action; he's also exceptional on the mic and in backstage bits - I love what he and Zack Ryder are doing and I am hoping it is going to head somewhere.
I think his smaller frame (that is, not being at all bulky, but more athletic) obviously hasn't held him back in a company well known for it's muscle preference. I'd even go so far for crediting him, by speaking volumes through actions, of convincing Vince and the other higher ups of WWE that a smaller build can actually work.
I'd would love to see him do a program with Christian in the main event. And for those of us that like Christian, credit to Edge is due, since he helped convince WWE to bring him back. I also think he would make the perfect transition to manager one day and/or head up another stable, as we've seen him do in the past. He is a TRUE tweener, able to be booed and cheered at the same time - but it's still a pop right?
One of the things I respect most about Edge is his abilty to read the crowd and play on it. One thing I am a bit over is his "crazy-eyes" - almost as hard to stomach as "Psycho-Orton-Mode" - now there's a guy who could have learnt more from Edge, acting wise (although Orton has gotten better). I would even like to see Edge reform Rated RKO or team with Jericho again, maybe with Christain. Yeah, the Canadian Connection or something