As someone mentioned before, the power increases sort of get diminishing returns at some point unless you bump up your software.
I guess for camera stuff and pushing more pixels that helps, but as it stands the way I use my iPhone 4 currently I don't have a need to upgrade, not even for LTE.
Was hoping for NFC but I guess that's a bit too soon until retailers get on board with that stuff.
I think the other thing tricking people out is how it looks...it really does just look like a taller iPhone 4...which is fine, but it can go a long way in people thinking it's just a more beefed up 4S.