I know other method, but alot people won't accept it, because it'll make repair-alt totally useless and non-repair character pain in ass to use weapon:
Make repair skill only affect how fast your weapon/armor deteriorates. I know it affects this already, but you can make it affect even more, and make weapon impossible to repair yourself (that's why you need repair alt), make it possible to do for caps (or mats) at various guntraders.
So, now a character with low repair skill will get his weapon on 1% with every shot and break his armor on 1% with every hit, and his equipment will deteriorate with low speed with atleast 100% repair, and really low speed with 200% repair, and >250% repair will allow him to use his weapon/armor for ages.
Yes, I know, it'll totally kill current repair system, because it's totally different way, but it makes repair skill useful on atleast 100%, and.. of couse... one step to kill alting.
Edit:
For low repair skill characters who want to pwn all for a long time without changing weapon, you can add "Reliable" weapon perk for such weapon as 10mm Pistol, Sawed-off Shotgun, Grease Gun, Tommy Gun, FN-FAL and XL70E3 (may be become more widely used).
"Reliable" perk (partly stolen from JA2, in JA2 this weapon perk gives less chance to weapon to misfire and break, in other words "reliabe" means weapon easy to use) = if your repair skill <100%, then your repair skill conisder as 100% for a weapon with this perk.
So powerbuilds with ~20% repair skill will deteriorate thier LSWs and sniper rifles at so fast speed so they had to have another weapon in inventory in case of breaking first, but they can use FN-FALs and XL70E3! Also M60 (noone uses) might be reliable too.