As I recall, Smeargle was banned for the ability to mega evolve TWICE. Once with Dragon Ascent, and the other with a Mega Stone. It was a bit of a mess, though it might be better with a single mega stone... (or maybe Banettite says no...) Manaphy was, and still is, too powerful for the metagame to handle, and it largely came down to guessing the mega stone to even have a chance at beating it. Obviously, that was very unhealthy...
Dragonite does more than use a new Fairy Extremespeed. It could also wield a Flying type one.
....Actually, it uses just about every legal mega stone pretty well, so predicting a Dragonite in a competitive environment is extremely tricky. The Pidgeottite set specifically takes on most of the listed counters to the Altarinite set above with a combination of Hurricane and Thunder. You can test it if you want to, but it will probably end up banned again in a few days.
And now, for some various thoughts from someone who has played this before...
-I think Volcanion deserves a B+ ranking at the very least, and for its Diancite set alone. 130 speed might not seem like much, but paired with 170/190 offenses, it is terrifying for an unprepared team. It even can smack Blissey pretty hard with a Superpower. 80/80/50 defenses are not the best, but at least they allow Volcanion to take a resisted extreme speed. The main problem it has is with dragons, and even those can be hit pretty hard with a coverage move on a possible switch.
-Aggronite should be considered on Tyranitar. Most people are content to simply lob a Fairy type E-Speed at the behemoth and be done with it, but replacing the Dark typing with a Steel one changes this entirely, and makes Tyranitar pretty competent defensively, particularly with the sandstorm up. It may fall to a Close Combat or an Earthquake, but regular Tyranitar would not want to take those hits, either...
-The lower echelon of Pokémon are pretty unexplored, and should necessarily be counted out from discussion just because they are not (seen as) good in standard play. For example, I've used a SpDEf Aggronite Vespiquen, and it actually worked pretty well early on. ...Except for the surviving Entei part. And handling steel types in general. (It does deal with Refrigerate Weavile and Kyruem exceptionally well, though.) When this remerges as the OMoTM, I'll add more to the underutilized section, and if I find some other hidden gems.
Dragonite does more than use a new Fairy Extremespeed. It could also wield a Flying type one.
....Actually, it uses just about every legal mega stone pretty well, so predicting a Dragonite in a competitive environment is extremely tricky. The Pidgeottite set specifically takes on most of the listed counters to the Altarinite set above with a combination of Hurricane and Thunder. You can test it if you want to, but it will probably end up banned again in a few days.
And now, for some various thoughts from someone who has played this before...
-I think Volcanion deserves a B+ ranking at the very least, and for its Diancite set alone. 130 speed might not seem like much, but paired with 170/190 offenses, it is terrifying for an unprepared team. It even can smack Blissey pretty hard with a Superpower. 80/80/50 defenses are not the best, but at least they allow Volcanion to take a resisted extreme speed. The main problem it has is with dragons, and even those can be hit pretty hard with a coverage move on a possible switch.
-Aggronite should be considered on Tyranitar. Most people are content to simply lob a Fairy type E-Speed at the behemoth and be done with it, but replacing the Dark typing with a Steel one changes this entirely, and makes Tyranitar pretty competent defensively, particularly with the sandstorm up. It may fall to a Close Combat or an Earthquake, but regular Tyranitar would not want to take those hits, either...
-The lower echelon of Pokémon are pretty unexplored, and should necessarily be counted out from discussion just because they are not (seen as) good in standard play. For example, I've used a SpDEf Aggronite Vespiquen, and it actually worked pretty well early on. ...Except for the surviving Entei part. And handling steel types in general. (It does deal with Refrigerate Weavile and Kyruem exceptionally well, though.) When this remerges as the OMoTM, I'll add more to the underutilized section, and if I find some other hidden gems.