My wish is only a small one, nothing special. I think that the elemental weaknesses are a little too potent (fire+2, lightning+2 especially). So I think we could use an elemental resistance enchantment. It shouldn't be too powerful, even a fire-1 or lightning-1 could be enough, that way it doesn't negate the weakness, but still makes it better. On the downside it would mean at least 4 different cards, that would take up 16-24 space in an expansion. So what i thought there could be an elemental resistance enchantment, and you should put an elemental token on it showing the resistance type. 12-18 card space saved:D.
Other variation could be a resistance with all elements-1, or you could put a token on it and that would mean its -2 from 1 element. For now it is tough to use certain units against certain mages, but this way for some extra money you could summon them in the right situation.