Quote Originally Posted by Maveric78f View Post
cast > play since M10.
there is never caps with card's types.

Apart from these points I agree that your wording is better than mine. I'm still not sure it's good enough.
I'm not sure how to properly word activating an activated ability of a permanent card in a graveyard that you just sacrificed. I suppose you could say "Choose an activated ability of the sacrificed Planeswalker and activate it without paying its costs." It just sound weird though.