[pre-PS edit] I've got no complaints about the current models' size, style, screen, or -- especially -- the strap connection (which I think is the biggest advantage the AW enjoys). I'm fine with the OS, and although different materials would be fun (other ceramic colors, titanium), I don't think they're necessary.
[/edit]
The biggest change I could see worth making would be adding cellular (in other words, "I concur"). It really depends on how it's implemented, though, especially how it would affect battery life.
However, users would need to understand the caveats of trying to do so many more functions on an inherently limited interface. There isn't going to be a Safari-like browser, and there shouldn't ever be a QWERTY keyboard (or even DVORAK). Scribble is a step in the right direction, but it's still not perfect.
I would be forgiving of limited functions if I could take it without my phone for a run or bike ride and know my wife could still reach me. But that's a pretty limited case, even for me, and I don't know if it'll be worth the effort.
What I can't predict is how the broader user base (or more importantly, potential users who haven't bought an AW yet) would tolerate a partially-functional cellular connection.
