1) WP absolutely needs a brightness toggle. This is a basic requirement for any phone OS. The 'auto' brightness setting is ok, but just isn't enough for varied lighting situations.
2) This brightness slider needs to be implemented into an overall control centre, much like iOS and Android. It makes sense, is very practical, and is discrete...coming up only when needed. Currently on WP OS you must have buttons pinned to the home screen to access simple controls. For all the time Microsoft had to work on Windows Phone OS, they missed some simple things. I heard this control centre concept is to be released in the next update, is this true? The screen rotation control is another utility that needs to be implemented into the control centre.
3) The ability to organize the list of apps. Scrolling through the whole list is cumbersome to say the least. There are better ways than a list.