The need of Cleric Stance is even more noticeable after level 50 since before then most caster gear gives equal amount of both, mind and intelligence. So your int based damage spells have something to work with. However after the 50 the gear is role locked and you as AST have mind gear, leaving your damage spells very little int to use. Except if you switch them with CS and let your damage spells munch on your sweet amount of mnd (that's pretending to be int).