The builds certainly don't seem equal in power to me. There is a big difference between bringing a well-built shiradi caster and an assassin into the new series. Your wizard is a solid build with past lifes, gear and game knowledge and failed. You completed with cheats on a difficulty scaled for 1 person. Assassin and Cleric would be a bit more challenging than wizard I would think although I didn't try it with those classes.
Do you have epic ring of spell storing and bauble? I am just curious if that was used in addition to the spell point potions you used to complete.