Long story short:
1) transparent statistics
2) constantly visible transparent weapons

And here's why :

It would be nice to have the possibility to make teams life statistics transparent just like you can do with hog names (del key). It can even work with the same button. The problem is when you have many teams in game and hogs are at the bottom of the screen. Stats are covering hogs and map and you must shot blindly. Sure you can move camera with mouse but try to do it in shoppa or when you're out of time. Transparent stats would make life easier in such situations.

Second transparent thing i would love to have is armory (the thingy under right mouse click). Using function keys to choose weapons is nice, quick and pro but you must know your weapons. It's not so trivial in highlander, shoppa or similar modes. So it would be nice to have your weapons constantly shown and not bloking your moves (like now). Transparency would additionaly make better usage of that part of screen. You could make it fully visible when mouse is over it.