I do not think that I implied that...
Most of the good cards for monoblack are already unrestricted though. Necro, I THINK, could bring monoblack back completely as a respectable deck. That one move, unrestricting Necro, I mean, could do it. The other tools are already there. Whether or not that would be TOO much, I'm not entirely sure, but I think enough people are afraid of Necro that it isn't a candidate for unrestriction...
Demonic Consultation/Demonic Tutor would boost the power-level of several decks if unrestricted. I'm not sure what would dominate with either or both of them unrestricted, but I'm doubting it would be monoblack or even all that black-heavy...
I'm not even sure if anyone would use Doomsday unrestricted. But I do not see how it would give monoblack in particular boost in power...
Entomb might help some Dragon deck or something, although Bazaar is a far superior tool for that deck. It could possibly help Reanimator type decks or something. It might help monoblack too. I'm not sure.
Mind Twist could do it. Mind Twist could do a lot of things, actually. It's been either restricted or banned for as long as I've been playing. I'm not sure what devastating effects its unrestriction would have in store for the metagame. I would concede that it could definitely strengthen monoblack though...
Yawgmoth's Bargain wouldn't do much for monoblack. Its unrestriction would help two types of decks: insanely broken combo decks that kill just about everything in today's environment AND any decks that happen to be able to withstand that kind of power.
Yawgmoth's Will is another one I'm not sure about. I think it would help multicolored decks more than monoblack, but I'll put it in the same boat as Mind Twist. So I think that of the restricted black cards, there are three (Necropotence, Mind Twist, and Yawgmoth's Will) that could push monoblack control back into tier 1 if unrestricted. Of these, Necropotence seems the most likely to do so and Yawgmoth's Will seems to the most dangerous (not sure what would happen if it were unrestricted, but it wouldn't be pretty).