- Relax level cap, set it at 30. Including HP gain + two more perks.
- Limit number of alts to three.
- Have a relog timer.
- Relax skill requirements for sneak, lockpick, and steal to reduce need for alting.
- Bring back the Gifted perk or make stat modules available through hard quests / special encounters. Make it so each character can only use a limited number of these, 3-4 max. Or make it so if you use stat modules / Gifted, that you can't use drugs.
Edit: You could also scale the HP a little of the usual "buffed" PvE critters when players reach the level 24-30 area.