I see this card as an attempt to encourage using allies for regular blocking and not just chump-blocking. There are a few Protection and Basic allies that are especially good for this:
-Groot heals after every block. So he can take a hit, heal, ready, and potentially take another one (or toss in an attack or thwart in the hero phase).
-Rockslide has a boatload of HP and retaliate, so he could potentially block multiple minions to get some chip damage in.
-Victor Mancha reduces incoming attack damage by 1, so he could potentially stall two minions forever.
I think it'll likely take a little bit more of a push to make this a fully viable strategy, but it definitely gets the ball rolling.