Sorry for the necro, but I have to say this is really a great idea. I was actually just about to make a Time card of my own that was really similar to this, but instead of leaving a Golden Relic it would leave Ruins, which is basically a deadweight permanent that does nothing and is immaterial (good thing I thought to check in the Crucible first...). This adds an interesting extra dimension that can potentially benefit the opposing player.
Voting for in the Crucible and hoping this gets into Forge.