I actually think Togekiss is balanced in this tier atm.
Please don't hate me. Here is my rationale:
With mega pidegot, beedrill, staraptor (all balanced in the tier imo), strong, fast u-turn/bird spam is really popular. With that, things like Raikou, Rotom-H, Bronzong, Metagross, and Jirachi are all really good. they check most of the big threats (esp bronzong). Mega Aggron is also really popular atm, since it beats crobat and the like. Things like diance and the like beat togekiss 1v1 unless it relies on paraflinch, but if it's paraflinch, it has to forfeit a better coverage move, recovery, or heal bell.
And old threats like Mega-aero and the nido's still beat the defensive/specially defensive defog sets. The speedy set beats bulky offense (chandelure etc), but bulky offense runs like mega gallade and fast bulky mons now. Togekiss is a threat if it gets to +2, but a lot of teams will be able to stop it from getting +2.
Togekiss also checks some of the meta. SubCoil/DD Zygarde is one of the best late game win conditions, and togekiss can stop it if it only runs dual stab. Haxarous now has to run poison jab as a coverage move (to hit fairies anyway), so it allows things like forry to be more viable by switch stalling if you get a toxic or something on it.
The most OP thing in the tier would probably be mega-altaria (imo). Everything else I think is easily checked by the tools we have in UU.
now if we could only have victini back to help check some of these big fucking threat...
Likewise, I have been toying around with Mence and Volc. Volc is great because it doesn't allow for florges to keep coming in for free, but it is still beaten by a lot of things, ie crobat etc. It is pretty manageable because of bird spam. If it gets +1, it can be a wrap, but scarfers still exist, and even then, fire types completely shit on it if it lacks hp rock. Volc is also beaten by scarf mence which is the best late game scarfer imo. Rocks are really important in this meta, as always, and now more than ever, hazards are key to victory.
Mence is the same story. MixMence is great, but I think the scarf set or subdd is definitely the best. It outspeeds hydregion and haxarous, even at +1 (if scarf), but if it opts to run a non scarf set, it's beaten up because base 100 doesn't mean anything anymore (lol ie mega zam, drill)
tl;dr all these big threats that were broken in xy uu seem to be a lot easier to manage now that we have a bunch of megas and such to deal with. plus the meta has evolved :]
Mega altaria is definitely borked. The special set is absolutely savage, and honestly, the dd, heal bell, return, and roost set just destroys so many teams. A lot of the times, if you play perfectly, the person using it will win simply because it can wear down its counters while it can heal up whenever it wants. It's one check would be like bronzong or forrey, but those are handled by a fire type, or really a strong fighting or bulky water. Anger managament is using the most op team of support + mega altaria, and there is almost nothing you can do against it since a.) if you run nido, easily worn down, you have to catch it on the switch, b.) dragon types literally can't touch it unless it runs poison or steel coverage, most of which are garbage moves in any other situations and c.) status doesn't even wear it down because it gets heal bell.
It's combination of speed, bulk, movepool, and how easy it is to support is honestly retarded lol.