The only way to stop alt using, is to make each build usable and multi-faceted. Who would use alts if their toon could do everything? If there were some more quests to raise your barter, your lock pick, your guns and unarmed, then people would stop using alts. Until then, I'm going to have an alt with 300% lock pick, and alt with 300% sneak and silent death, an alt with energy weps, and an alt with 300% stealing.
No body is going to make good enough friends on this game to trust people to do shit for them. I'd rather quit than rely on some one else. Make the game challenging for single players but make it extra challenging for teams.
I can't stand it when I get online to play a "game" and it turns out to be nothing but "work" in disguise.