The Nerubian Egg seems like it's going to be a little OP in aggro decks. Pop one of those down on the field and suddenly you've got some serious AOE protection.
I watched this video from Noxious about his thoughts on the new cards:
He's got some good thoughts on how these cards might work. I mean, imagine going second and opening with turn 1 Undertaker, coin into Leper Gnome. That's a 3/2 and a 2/1. Leper Gnome kills the 3/2 the opponent throws out, and then you play a Nerubian egg, giving you a 4/3 and a 0/2. Best case scenario for your opponent is that they have a Wolf Rider at that point, or some other 3 damage removal. Even if they do, though, a turn 3 Void Terror would be devestating. It could eat the Egg, leaving you with a 4/4 and a 3/5 on turn 3, while your opponent is likely to have little or no board presence.