Either completely remove useless cards, like rage or clone, or always have them in same draft so that each player has atleast one nearly useless spell.
Avoid giving 1 player too many choices over spells or win conditions.
And probably most important: In one draft should be ONLY similar cards. For example a wizard or a witch, fire spirits and ice spirit, log or zap, arrows or fireball and so on. Often you can chose between a card and counter to that card, which is stupid in my opinion it is something like minion horde or wizard for example, shouldnt be like that. Another example from recent game, i could chose between a barb spawner and ice spirit.. Like wtf? Wheres the logic or fairness in that one? Would make more sense to match gob and barb spawners, and spirit with another cheap card like fire spirits or skellies.
I have a lot more, more complicated ideas to balance draft but im gonna exclude those because its probably way too hard to implement those anyway.
Also if normal draft mode gets balanced, they could add something like draft mode extreme, where its actually 100% random and everything is possible and one player literally can get ebarbs, rg and hog and other only support cards and spells, not sure if that should be a challenge that should cost gems tho.
If you disagree, explain why exactly and with what