I think people are seriously underestimating the impact that Dugtrio would have in UU. For one, your typical stall team would be completely on edge with this thing around; it can take out most Chansey, Clefable, Registeel, Drapion, Nidoqueen, Omastar etc with relative ease. Even Steelix and Regirock would be vulnerable at less than ~70% health. It would beat a lot of offensive Pokemon too, like Blaziken, Espeon, Mismagius, Ambipom and various others. Unlike other trappers it has lots of speed, and enough Attack power to make good use of it.
Also, if Crobat is somehow allowed to stay in UU this time round, the introduction of Dugtrio would probably be the final nail in the coffin. Who supports who more I wonder?