I achieved omnipotence last night with Govannon. One key I found that really helps the process is to shoot for making a hero archmage omnipotent, but to avoid reading any spellbooks until the hero is at 100xp. Any books read before then are essentially wasted xp (xp you would have gotten anyway through the Hero promotion). Books read after 100xp from Hero are extra xp that you would not have gotten. Same goes with casting Arcane Lacuna--do it after 100xp. Using this method, I found achieving omnipotence pretty easy. Hero gave me 100xp, Lacuna gave me 40ish xp, and I had 13 spellbooks which gave me all but two of the needed Level 3 promos. After purchasing Omnipotence I still had 50ish xp left over! The only thing I found lacking was that, by gaining all your promos at once, this method prevents you from actually using any of the Arcane Mastery spells. It would be fun if I could actually go kick some ass with Omnipotent Govannon while waiting to win, or something. And I have one more suggestion: make Omnipotence remove the "one spell per turn" limit. What's the point of your omnipotent archmage having hundreds of spells at his disposal if he can only use one at a time? Let him use them all every turn if he wants. Let him summon every elemental and all his Shooting Stars, Curse all his enemies, give Might to all his allies, AND summon a Tree of Life if he wants. Is it ridiculously overpowered? Sure it is. But he IS omnipotent.