Why is Ursaring not on the ranks?
This thing is a threat to any wall, it almost always forces sacking at least one pokemon, or a risky predict of the SD because it can hit hard even without boosts.
I would say it fits B or B+.
And I agree with Keith here, Porygon 2 definitely does not fit Rank A, it fits C or B at BEST.
It can be trapped by Subversal Dugtrio but it also can revenge kill CB Dugtrio which is nice.
Another useful thing is that it doesnt force you to go Blissey everytime your opponent has Jolteon out.
I'd give Dugtrio Rank A, trapping Metagross and Heracross, the top tier threats is just wonderful.
People say that one of its downsides is that it gives the opponent a free chance to set up Gyarados or Charizard which can be fatal, but that also happens to any Choice Bander locked on Earthquake so I really don't get this point.