The floor on these in a deck triggering multiple upkeeps is still very high, especially when youre playing one, become the monarch, and then get your combat damage trigger from Obeka
pretty much any Fire Pokemon with dangerously powerful flames
The reason for this is mainly that since the printing of Ragavan, Nimble Pilferer, Dragons Rage Channeler and Murktide Regent the tempo archetype reinvented itself in being primarily blue-red and making Deaths Shadow not a necessary creature for tempo shells anymore
So that Jace, The Mind Sculptor really is worth his weight in gold.
The flavor is a little off, but the mechanic played well, was generally liked, and clearly ties into Zendikar's land theme
He does sit high on the curve for Artifact decks, but the potential to keep fueling the fire may be worth finding a spot for him