Then my post is missleading. Sorry for that. From my point of view, its not out of balance by ITSELF. Maybe other things made teh magic less powerful compared to skull damage (but not point of this topic).
With the introduction of kingdom bonuses there are much more bonuses for health, armor, life as ffor magic, but that suits with the fact, that upgardin a card with +magic abilitie only gets +1 magic much less times then the other stats.
I highlighted Keghammer, coz his abilitiy reduces magic by a fixed amount and through the recent changes, it made the ability less and less valueable. Simply compare it to a cards like “Do x+Magic damage and silence (or poisen or entangle or drain their mana)” While these cards second abilities still have the same impact as 6 mounth ago, Kegs “Do x+Magic damage and reduce Magic by 3” got nerfed by quite a margin.