Too similar to CR and Margrave to actually work
The biggest problem is that it's strictly superior to both.
Wrong! Say it's my turn, there are three cards left in my deck. I don't want to trigger the reshuffle. If I play a Margrave, I can get those three cards and attack. Playing the Margrave room will trigger the reshuffle!
I think reshuffle triggering should usually be ignored when talking about strictly superior effects. If you start counting it, you open up a slippery slope that will say that no card is ever strictly superior to another card.
Example: Gold's effect is not strictly superior to Copper's because you'd rather it be a Copper while you are possessed.
I mean, yeah, you could take it that far, but it isn't really useful for discussion to do that. Gotta draw the line somewhere.