More efficient and flexible Gravedigger for green. First of, I think this is too powerful, and second, this is problematic at common since you can loop just two of them together + you know, it generates card advantage so the traditional red-flags apply to it as well.

Mm. There's a reason why Gravedigger isn't common anymore. I presume it was because Wizards was getting sick of the Gravedigger gets Gravedigger strategies. It's not broken, really. It just tends to bend whatever limited environment away from whatever Wizards is trying to mold.

Yeah, they've explicitly mentioned the Gravedigger loop being problematic in Limited