I might allow it... if anyone has played Diablo 1 or Hellfire... the shrines always came with soem text message etc: "Wisdom comes in cost of strenght" or something... So if one of my players wished for a permenent +1 casterlevel... i would roll 1d3 to determin a stat to lower; str, dex or con. Lower the stat by one.. and grant the +1 casterlevel..
Or.. i would make a "Power comes with age" and grant him the +1 casterlevel.. and transfer him to the next age category...
Or.. i would make a "Power comes with age" and grant him the +1 casterlevel.. and transfer him to the next age category...