u4e is pretty much done for UT, so fortress is what you see it. As for the overpowered wizard, get better opponents who know how to keep a wizard down.
Some classes cannot pickup every item, so it may be that you can't get the boots because of the class you are playing.
As for the drop in FPS, is a well known problem, the only solution so far that partially helps is that if you are using the u4efortress.bat file to run the game, try running it by making the manual .ini changes explained in the readme, and vice verse if you are running using the changes already. Some people it helps, others nothing happens.