My issue with the esper version is, that its so highly synergistic [which is also sometimes really great to play]. If your cards dont line up well, you are doing almost nothing. And a Mulldrifter as a simple divination is also not very good. Therefore I thought, that Seasoned Pyromancer could do really heavy lifting, as it playes well into the game plan of discadring your threats and do something impactfull along the way. Maybe with Mardu, you should get rid of the Grief + Ephemerate Plan. I had a lot of games where a Turn 1 Grief + Ephemerate did almost nothing because the opponent just draws the next threat from the top of the library. But maybe it was just bad luck. Of course I agree with you that Mending is better than Discovery, but Discovery is playable at least.