People are using dugtrio wrong, they're using him to try and atack pokemon that have a shred of defense. Super effective does not equal killing the opponet. Dugtrio won't hurt registeel. Use him to revenge things like blaziken or weakened roserade.
or you know, you could just switch duggy right into ant registeel attack, take off a chunk as it kills you, then send in yanmega and..win
The only problem with that is if registeel was a physical tank he could counter the EQ back for a dead dugtrio.And he completely counters yanmega with ice punch which leaves it at like 10% after SR if you invest about 100 evs into it. ALso Mega is OHko'ed after stealth rock by zap canon..
Currently, I'm tired of Yanmega. His ability to sweep through teams is disturbing. True SR, Priority, and Chansey/Regirock are decent enough checks but I'm just not sure. He is like the Special verison of Swellow but with two perfectly viable abilites, able to defeat its own checks with relative ease (Sleep, Hax, Roost, Reversal), better typing, and decent defenses.
Its not even, its finding time to switch in Dugtrio is the tough task. The only "safe" way to bring it in is after your Pokemon dies. People get ahead of themselves with Dugtrio but people need to understand that it has 80 Base attack, and most run Jolly, meaning it will get weaker.
I think the reason why its not lived up to the hype in this tier is that its set-up fodder and it can't find the right time to switch-in. I don't know, I'm not convinced yet with Dugtrio. Its dead weight for the entire match unless you have tremendous prediction to safely bring it in, even then, you still need big time walls to be sufficiently weak to grab the free kill. Overall Dugtrio will be sitting out the entire match..
Your second reason is just ridiculous - anything can defeat its checks reliably with hax, not just Yanmega. You can't cite hax as a reason why a Pokemon could be broken, that’s just silly.
minimum 44.07% damage
altaria switched in (75%)
bug buzz (maximum 30.93% left)
leftovers (maximum 37.18% left)
bug buzz (maximum -6.89% left)
not sure where "69.93% 2HKO with SR and leftovers" comes from
but yes lol altaria
^Why not use Ambipom to Plot pass, much faster and can still rip stuff up with Fake Out and Return.
It's very hard to fail a pass to Yanmega with this thing, which is basically the best Plot passer in UU. Yes, I know, Ambipom can do it too, but the reason to use Minun over Ambipom is Encore. With Encore, all you have to do is bring Minun in on any setup move or supporting move, and with Minun's nice Speed, Encore it, Nasty Plot, and Baton Pass. I know it seems counterproductive to use 252 HP EVs and Focus Sash, but Focus Sash is mostly there for Dugtrio. If you can keep Stealth Rock off the field, Minun is basically guaranteed to get the pass off thanks to the Focus Sash. If by some chance Focus Sash gets broken from Stealth Rock, Minun can still work with it's semi-good Special Defense to get the pass off (in case you're wondering, this is the reason to use it over Plusle).