I like both concepts, but I don't like them together in the same card (even the same element). This is basically because it turns a field of nothings (Malignant Cells come to mind) into Dragons in two turns. At the same time, it super-charges your Bone Wall. Then you can keep it going, turn after turn, no matter how many units are killed.
I would recommend matching cards, but Eternity and Rewind already provide a match to the auto-kill.
And just to be clear... I really like the corpsify-all-your-units concept. Very nice.