Anty
let's drop
The mons you mention really dont handle is well. Firstly, avalugg beats 90% of the tiers attackers, even then, specially defensive avalugg (its better set), has problems consistantly switching in (it looses 60% of health from + 1 crunch + rocks, or 75 % from two non boosted crunches + rocks). Golem takes >50% from a +1 crunch, which isnt hard considering it usually used as a lead, hippo takes even more from +1 crunch (about 60%). Both pelipper and licky lose >50% from a +1 crunch. Serperior gets 2HKO's by unboosted crunch. This is actually quite a lot of damage considering it is to the most physically bulky pokes in the tier and you also have to consider (as the leprechuan said) that these poke wont be at full health; you are not sweeping with mightyena turn1. Also the teams mightyena is put on are ones which try and weaken down the opposition for it to sweep, whether it is spike stacking, or multiple offensive threats (tauros, heatmor, etc). Mightyena also has a better match up vs offensive teams; where they dont have physical tanks like avalugg, they have frail mons that dislike taking unboosted hits. As a HO player mightyena is one of the biggest threats to my team, as if it gets a moxie boost mid game it can sweep with little prediction.My problem with the list of damage calcs is that it ignores the large list of defensive mons that can easily take hits from Mighteyana, and personally I've never had a problem with that because most don't carry pursuit to guarantee a moxie boost. Lots of things like Serperior, Lickilicky, Golem, Hippopotas, Pelipper, Avalugg, etc can handle it (sorry for lack of calcs, but on mobile device) and phase or kill it. My issue is that it needs a +1 boost to even take out a 4 defense Marowak. Yes you have to play it right late game for it to work, I've just never had an issue. That being said, I'm willing to admit that it doesn't deserve to drop below Arbok and Keckleon, but putting it on the same level as Basculin might be too much. I guess I'll have to go build a team around mighteyana now.
Tl;dr a drop might not be necessary, but a boost is probably pushing it
It is much better than basculin, who, imo, is one of the worst mons in b+. If your comparing it to anything in b+ it should be something like simipour, who is also a late game sweeper. Simipour has higher speed and a guaranteed boost move with nasty plot, however, is still outsped by common stuff (like tauros), lacks priority (which can also be helpful outside of sweeping) and it isnt easy to set up with simipour due to low defenses