If it comes with steampunk infantry, mutated elementals, and shoots all manner of brimstone, ice shards and electricity all over the place sign me up. I'm not conventionaly a fan of enforcing card design that survives on dependencies (so, cards that are below rate by themselves that require other cards being cast in order to be competitive) as that is a slippery slope that restrains deck choices, but provided the new faction's cards were to be balanced around a healthy game state where the usual culprit spells (eruption, lava field, coldsnap, disenchant, ravage and so on) were considered (so, not designing the cards in a vacuum, but also not considering always having access to them) there could be a decent set to be made out of this idea.
I'd like to see some units that have non-combat supportive text that affects either the owner's or all friendly players' spells in their vicinity. So maybe a boost to damage spells, or extended CC duration, or some immediate void refund - and of course some nice active abilities that have a lot of flair.