Seems a very complicated and fiddly way of saying "It keeps coming back with a -1/-1 counter". If it can keep the -1/-1 counters in all zones, why bother with the "exile it instead"?

Just say "When ~ dies, return it to the battlefield at end of turn with an additional -1/-1 counter on it."

Seems kind of boring to do it that way, but I will think about it.

OK. I removed the whole exile thing, saving it from graveyard hate really isn't that important. How is it now?

Are you supposed to be allowed to target this with Dispatch? Does it matter how many artifacts you control, or whether that number could change in response?

(Equinox is not the most shining example of a rigorous template the game has ever had.)

Also, this will eventually come back as a 0/0, then a -1/-1, and so on for what's mostly some pointless busy work every turn, but generic ETB and death triggers will demand that you play it out, and play it properly, turn after turn as its power and toughness get more negative each time.

Since Dispatch would only exile it if its controller has Metalcraft, it would only be untargetable if metalcraft is activated, since Dispatch can't exile it if metalcraft isn't active.

I'll have to fix it so it can't come back after being a 1/1. Working on it.

I was hoping this would reference Grove of the Burnwillows.

The card seems like it has a lot of things going on. Is the first ability to prevent allow it to continue coming back more easily, by preventing shenanagins that don't cause it to technically die? If so, you may be able to wrap the abilities together. Here's my twist:

"Whenever ~ dies or is exiled, if its toughness was greater than 0, return it to the battlefield at the beginning of the end step. Put a -1/-1 counter on it.

Counters remain on ~ as it moves to any zone other than a player's hand or library."

My other issue is that a grove of trees shouldn't be able to attack. Putting defender on a mythic would be no fun, though.

Its not a grove of trees :D Its an grove of Elementals!