This is my take on a Smallpox based deck. It runs efficient, attrition based creatures and wins via Messenger, Crusader, or Affliction.

Some cards that you may be questioning:
Black cat is in as a creature for smallpox,
Ravenous Rats is in as a discard spell that can be used for smallpox,
Distress is my budget version of Thoughtseize. The deck can afford to wait a turn, whereas it normally can't afford the 2-8 damage from Thoughtseize.
Shrivel and Blood seeker are for the token matchups, as the single-spot removal has a hard time with these two for ones.
Chalice of life comes in in a hyper aggressive red matchup to help me recover. It can also be used as a clock for control decks.

I feel that this deck is very well positioned in the current modern meta, as it can handle pretty much every threat out there. Goyf, Geist, and fatties aren't an issue because of Geth's verdict and Smallpox, LotV isn't an issue because I seldom have any creatures, and when I do, it usually helps to kill them anyway.

The only change that I think I should make would be replacing Grasp of Darkness with Go for the Throat.