Brood Keeper The nanny of dragons
Assuming you're playing a bunch of Dragons, defeating the battle shouldn't be a problem since you'll have a bunch of big evasive creatures, although there probably will be times when it's better to just hit your opponent's face and then try to burn them out with the front side of Invasion of Tarkir rather than flipping into another Dragon that dies to a wrath
Any creature you control that couldn't be targeted by the original spell (due to shroud, protection abilities, targeting restrictions, or any other reason) is just ignored by Zada's ability
Right away, when you cast it, you get to blow up one of your opponents colored permanents
Even though it costs one mana more, it's still a good card, especially as it's now mono Blue instead
For five mana, for example, you either get a 6/7 with trample or a 3/4 that deals three damage to another creature, and those are both pretty good deals