Compare to Fated Return. You don't need to up the cost that much just for +2/+2.

This is pretty cool. But to me it looks more like an uncommon than a rare. It's basically Vigor Mortis (or Miraculous Recovery) with Battlegrowth stapled on. Uncommon is the default rarity for Zombify / Rise from the Grave effects. There are occasional rare Zombify effects, but they usually have some specific reason. Beacon of Unrest had to be rare because of its cycle so they added the ability to get artifacts and to get things from any graveyard. I'm not sure an extra +1/+1 counter over Miraculous Recovery is enough for rare.