I'm not sure Murder will be getting an upgrade, particularly not at common, and especially since black doesn't get unrestricted, efficient removal at common anymore.

Hey, Terminate is still a common legal in all formats.

I'm aware. It's a very good card.
The default way to appraise sets on Multiverse is to assume the user is utilizing the modern color pie and creating a set that might appear in Standard rotation. Wizards doesn't like to print efficient removal at common anymore because they believe it makes limited better.

Just to reinforce Link's point, observe Flesh to Dust, the up-to-date version of Murder :( Also compare Grasp of Darkness to Throttle/Lash of the Whip.

Personally I'm fine with a custom set containing common removal at Murder's power level. But be aware it is against Wizards' current design principles.

IMHO, Flesh to Dust really only sees play in limited, I think the set should have something like this at common even if Wizards wouldn't do it.