thank you. i noticed it only today. Right now i'm glad of course that i can clear bosses on hell difficulty this way, (sometimes this is kinda the only way), but generally i agree that it should be limited. Maybe like 1 stack on lvl1 spell, 2 on lvl 4, 3 on lvl 7, 4 on lvl 10, 5 on lvl 13.
Yeah... stacking a bunch of firewall/lightning wall after elemental drain with a manashield and etherealize and a whole shit ton of mana potions may have killed a hard enemy or two for me so far....