If it is Fallout, then less weapons, very wide condition scaling. 100% guns should be god-like, but unattainable via any kind of repair, only found in pre-war locations. Also(and I don't know if that's how degrading works in F3), weapons should degrade faster than armor, with armor degradation rate set by some kind of a durability rating, i.e. leather jacket gets destroyed after few assault rifle criticals, PA only affected by big/energy weapons and really high end small guns.
If it was any other game, I'd say more guns, less scaling, but in Fallout it makes sense to put effort into maintaining your equipment. As of how many are too many weapon choices, I'd say that F3 got it about right.
Oh yeah, I'm also all for the mods, but I don't know how mods would relate/modify weapon's condition scaling, i.e. mods can only be installed on a weapon with 50% or higher condition, or mods can be installed on a weapon with any condition, and it will raise weapon's condition 10%
EDIT: I also think that no traveling traders should ever be able to repair better than a freaking store keeper with a workbench next to him/her.