If people are scared of players exping on molerats forever, we could put a limit on how far you can level one char in normal way and then put dedicating exping grounds in visible unsafe areas. Put some nasty monsters in towns and other unsafe visible locations, like Sierra and Mariposa. These monsters could then reward the chars with say, Advanced Experience which allows levelling over max cap. In additon every tc town could have their own exping area but away from tc zones so that those nasty monsters wouldn't bother tc fights.
This brings more activity in towns and encourages hunting in groups because you might be jumped on at any time.
The method of exping in these locations should be more like search and destroy, rather than kiting a massive mob like in Diablo cow level. This is because if you get jumped on while exping, you don't have to fight the players and the huge mob.
There could be other forms of getting advanced exp, like fucking whores in Reno or drinking currently pointless drinks at unsafe bars such as the ones in BH and Redding.
Okay, but the suggestion did not mention any limits on HP or skill; I was referring to that. But that would still be too vague to say because some builds need more combat skill than other types, and even passive skills can help with combat, like outdoorsman (getting to the combat). I think that choosing one thing should limit the other thing, not find a way to have 300% in almost everything.
Well, the point when someone has 300 od as untagged skill, everyone else has car tents. Personally I wouldn't hurry with outdoorsman on my pvp char because buggies in spawntents would be faster option and in the end you will have so many cars that you hardly ever move with outdoorsman. Besides even now, 300 od pathfinder proxy is used as taxi. Outdoorsman actually needs a buff.
What's more troubblesome are sneak, fa and doc. But no worries, sneak is affected by gear and it's very useful only with silent running and ghost perks.
What comes to doc and fa, it's not a big deal. 300 would be the standard ammount of doc and fa for all chars in the end. There could be variations depending on character's special and equipment which could have big effect on the outcome when the skill was used. This way skill 300% wouldn't mean "As good as superman" but "as good as this specific character can become".
So for example perception and intelligence could give bonuses to doc and fa to discourage int1 builds.