That ultimate is terrible and will pretty much never do any damage unless you're playing land destruction or a lot of bounce, neither of which is in black. You give the opponent three full turns to dump their expensive spells.

There's a tension between the card's -X ability and the -9 ability. If your opponent dumps their hand, they'll have a lot of killable creatures. The ultimate exists as a way to force a player into the -X ability, as well as an option against decks that don't run creatures (notably control decks that keep full hands).

-9 is still quite high. I wouldn't cast Wit's End for Suspend 3 - 2BB, and while this obviously isn't exactly the same, you still get my point.

Eh, the +2 ability seems kinda weak, in my opinion. Maybe make it 2 life? Or something else entirely?

The main perk of the +2 ability is the +2. Given what the -X ability is, I can't make the +2 too good.

As for Wit's End, the main problem with a 2BB suspend 3 version is that the opponent dumps his/her hand. With this, the same exact card punishes hand dumping. When the ultimate hits a reasonably full hand, it pretty much ends the game, so I am a bit wary about lowering the cost.