That is why, in AD&D you only saw gods with incredible attributes. These guys on Kulthea (not gods, just immortal elves and such) would be running around with the equivalent in AD&D of 21-30 attributes in ALL - even physical stats for mages. A little "over-the-top" I say. You couple that with the fact that they are all 50th to 100th level (with a few very special individuals over 100th level) and you have some seriously godlike NPCs.
I think they would have been fine if you keep the levels (they have lived for millenia in most cases), but lowered their stats, especially the ones that are not key to their profession. Like a magician could have his strength in the 90s - not in the 110-115. If you don't want it so "low" then go with 101-103. That is still much stronger than 99% of the population. His prime stats could stay as they are so they are still a major bad a$$ in what they do, just not also one in something the profession is not supposed to be (though they are still really great there).