So the one weakness of this design is that the turn you cast this you either are already in a very comfortable position (and don't really need to "win more") or have probably a rather small hand and put yourself on a clock that doesn't seem to mesh well with the controlling deck that might use this.

In Constructed that might just mean that you start chaining this to put actually your entire former library into your hand, but that's using 14 mana to get there over probably turns. And you haven't done anything else by then.

I give you credit for finding an effect that is decidedly different from Emergent Ultimatum.

I noticed, that this is the "Sultai Ultimatum" in the sense that it is black-green-blue with black as the focus-color (where Emergent Ultimatum focuses on the central color green), but the name doesn't seem to recognize this. You probably where going for something entirely different.

Nevertheless this would certainly fill your graveyard with cards to delve away.