I think this card is excellent in a sacrifice archetype, a super fun card overall and am slamming it into my cube.
However, I think people who don't support aristocrats AND run smaller powered cubes will be disappointed if they expect much from him.
He requires considerable setup before he becomes a power house, and if your format has a lot of decks that go way over the top, grindy decks that support him may not be well suited to that format.
In that kind of format I'd want my black agro decks to disrupt the opponents mana base/hand and/or kill fast as possible. Yawgmoth does neither.
IE he'd be stone unplayable in the MTGO vintage cube.
The more creature heavy and slower the format, the better. Against a green or white creature deck, yawgmoth seems utterly absurd.
This is more or less where I'm at on Yawgmoth. I don't think he's an autoinclude at all, though I'll be giving him a shot if I can get my hands on one. He does have one of the key advantages to being a good cube card, in my eyes: the decks that want him REALLY want him. But he's going to be very matchup dependent, and I think there are going to be a decent number of times where he feels disappointing.
This is more or less where I'm at on Yawgmoth. I don't think he's an autoinclude at all, though I'll be giving him a shot if I can get my hands on one. He does have one of the key advantages to being a good cube card, in my eyes: the decks that want him REALLY want him. But he's going to be very matchup dependent, and I think there are going to be a decent number of times where he feels disappointing.