Wynn

If I remember correctly, they aren't even able to do this, but, as other people have pointed out, they probably wouldn't if they could. The entire system is balanced around a maximum of 20 mana, and increasing that, even by 1 every 5 levels literally doubles that. That would make mana regen and intel extremely overpowered in the endgame. 1 mana meteors are already spammable. Add on a ton of extra leeway, and you could easily do 4-5 meteors with a single ice snake to reset costs and be fine. The same goes for all spammable damage spells; you could easily double a spell build's dps with this.

 

That would be so unbalanced

 

This isn't neccesary at all. Intelligence and -spell cost ids are easy to get and basically do the same thing, but better, because its like scaling up max mana AND scaling up mana regen