I am using a HTC Touch Cruise. When reading web pages, the wheel button is for scroll up and down the page. I hope there could be a setting place to control the scroll amount for each action. Because at the moment it always go up/down a whole page. I just found it's a little hard to connect with the contents on the previous page. I don't know how other phones handle this problem. If we can set how many lines to scroll will be good. I think even include the last line of the previous page in the view when a pageup/pagedown happens will help a lot.
And another minor thing is: if the application can mark themself as a reading/editing program and keep the backlight on will be great. Similar with the behaviour of Media Player in desktop pc's overrides the screen saver settings. And make that configurable too.