I have played this server maybe half a year, maybe more. (Is there a way to know exactly?)
This server is fun because there are very dedicated role-players. But this is a game after all, and many people still find a great enjoyment in leveling up and seeing the progression of your character, not only in RP aspects.
I have played PoTM A LOT. A great deal too much really, to be considered normal
Anyhow, as a pure melee barbarian, it still took me more than half a year to reach level 14.. and as I said I've played more than what is healthy at times.
(And this is during my free time) I work from 7AM-16PM everyday, so It's not like I've spent all my time in PoTM
Slowing down exp rate for me would make me consider quitting the server sadly, since I work very hard as is to get exp. And in my opinion it's good that you have to work hard for exp, but penalizing players too much because they enjoy killing monsters more than sitting in Vallaki doing RP for hours, doesn't seem fair.
We're all here to have fun. And some people are here for the RP, others for leveling. Some people enjoy both, like myself, I enjoy the RP aspects greatly (Even if I still suck at RP) but I also play this game because it's a game, and I enjoy leveling and killing monsters.
On another note, I don't think the server is 100% perfectly balanced because it isn't. But I do not think the problem lies in the exp rate..