Proposed Change:
Protect Artifact 1
Target Permanent or Stack of Permanents and all Permanents of the same name can not be targeted by any skill. Permanents that are played after Protect Artifact are unaffected.
This change would not have any affect on stacking permanents, but it would allow for multiple unstackable permanents to be protected at once. It would also protect the upped and unupped versions of stackable permanents for players with partially upped decks.
How it would work:
Player plays two Hourglasses. Player plays Protect Artifact on one of the Hourglasses. Both Hourglasses are now protected. If an opponent has an Hourglass, that Hourglass also becomes immortal. If a player plays a third Hourglass, that Hourglass is NOT protected.
The limitation to permanents played afterwards would be to limit abuse of permanents such as Dimensional Shield and Sundial. I am not sure what the ruling should be on how this would affect Bone Wall.