i don't like the retirement age - you have to play for many hours just to heirloom your weapon, and there's no point in trying to lvl more.
Everybody will just go lvl 30, retire, go lvl 30, retire - and i think that ruins the game.
I liked the lvl 15 retirement age, maybe lvl 20 but not more.
Then you have the choice between retiring and lvling, which i think is good