I look forward to welcoming our new overlords.
In seriousness though, this excites me a bit. It further pushes the limits of creatures in formats where this is legal, and it really does have strong potential. Basically every creature with power 1 or greater now has the ability to steal the crown or really steal it back.
An early monarch can also be really solid for keeper or just plain Jane tempo decks.
I'll wait till more stuff that puts the monarch into effect get spoiled though because right now I don't think Marchesa is quite enough by herself to get us there.