I'd greatly appreciate it if Apple improved their dialog system. It isn't uncommon (or at least it was in the past, maybe this has already been fixed) when performing an update in iTunes to get a large number of dialogs in a row.

Also, while it may be difficult, it would be nice if there was a way to improve the experience when running games that use Game Center. (They often force you to put up with the game running slowly as it tries to connect and it annoys you by showing you two dialogs; I think the typical OpenFeint experience is a little better.)

And mobile browsers should allow extensions.