This secret seems strong enough to see play in almost every mage deck until it goes out of standard. It pretty much fixes all the problems that keep explosive trap from seeing play. Most of the best minions are 3 health so explosive doesn't finish them off and you're mage so you have a hero power to clean anything up that didn't die. It also can't get activated by a weapon while there are no minions on board. Only downside is it doesn't go face but that would be broken with the amount of burn mage has.

This card seems like it can be really strong with deathrattles with the deathrattle activating twice like cairne making a super sticky minion. It's also insane on zillax having it come back with divine shield and taunt again to heal a ton. Also consider the difference between this costing 1 mana vs the 2 mana spell paladin had is a huge difference because usually you want to be playing it on the same turn as the minion you're playing it on so being able to do the combos 1 turn earlier is huge.

That's probably the point, they're adding more cards that generate lackeys so they need to dilute the pool a little bit so the lackey classes don't become too strong.

They're hurting priest right now so they can add cards that would be broken with mindlast next expansion, or at least that's what I'm assuming.