You should wait until you have Vito, Thorn of the Dusk Rose online, or something like this, and Cramped Vents becomes a removal spell plus up to 5 life loss for everyone else
Hullbreaker Horror's abilities are insane against everything, but there are also more niche options such as Avabruck Caretaker
Opponents in a Commander game will almost always have something they would rather be doing with their mana rather than paying Smothering Tithe's tax
For a single mana, you turn every Island you control into a double-producer
You can also blink this with things like Ephimerate, and it gets even more out of hand
While I think Azorius has the best of the best as far as Control cards go in Standard, I think there's something to be said for a few of the new Black spells in MKM