hooray!
I've been trying to tell my current DND 3E Forgotten Realms players how great Gamma World was. Now maybe I get to _show_ them?! Hooray!
Things that are very important to me:
1. Mutant plant/animal player characters. These are much of the fun of the game!
2. Random mutations don't suck. If random mutations exist at all, then they need to be handled very carefully. Perhaps random determination of a small number of mutations from which the player or GM can choose? That'd keep it mostly random but not unbalance the game. With a lot of work, truly random tables could be balanced, but that's unlikely to happen.

3. High-tech should still feel like magic. Entirely like magic. 2nd, 3rd, and 4th kinda reduced this feel somewhat, each in turn. This isn't Star Frontiers--anything involving technology should fill the same role that spells and magic items fill in D&D.
4. Pittsburk! (sp?) I'm from Pittsburgh originally, and my players all believe that everyone in the United States except for them are from Pennsylvania originally. This'd further their paranoia!
5. A careful balance of monsters, bad guys, etc. It's a fantastic setting, great for a light-hearted game. But I've still had campaigns run for a very long time, as a result of careful tweaking of the rules. I'll continue to tweak, but if y'all do most of the work for me, it'll rock!
Thanks so much!
Things that I don't want to see:
1. Robot/cyborg/cyberpunk characters. Eww. Rip 'em out. The game should focus on its strengths, and not try to be everything to everyone.
2. Internal inconsistencies. Some inconsistency is necessary, of course, but try not to contradict one statement with another one later on. That makes life difficult from a gameplay point of view, no matter what the affected rule might be.
Thanks again!
--Thaddeus the Overbearing