Just want to see the general position of the community on this hero.
Personally, I think the hero's practically perfect, the only problem is his ultimate. The minions don't prioritize towers, making it hilariously easy to stop his ult from pushing since anything that walks within about 500 units of one minion pulls them all off the tower.
The passive makes for great early harassment, and I like the stun. Corpse explosion is a bit iffy, but I blame that on the current bug which causes Gravekeeper to consume all corpses in the radius if he attacks while on more than one corpse (fixed internally, according to the bug report I sent in).