Alright Here goes something:
Mega Gallade:
In my opinion, I Believe that mega Gallade is one of the biggest threats in the metagame at the Moment. at +2 with coverage moves such as knock off, close combat, Psycho cut, and ice punch, It can 2HKo or 1HKO most walls in the tier, even Slowbro. But its Important to realize that Mega Gallade works only as good on hyper offensive teams, not balanced psychic. JUst look at this replay here
http://replay.pokemonshowdown.com/monotype-188342536 My Opponent was put On pressure by my trick scarfs and hazard pressure, and thats why he got sweept. On the other Hand take a look at this replay
http://replay.pokemonshowdown.com/monotype-196690399 here my opponent was trying to put the momentum on by me, but because of my Balanced offensive core, He wasen't able to do much with Mega Gallade, or at lest put the pressure On my team. Another thing: Gallade tends to have a 4 slot move Syndrome. From what I Have seen its Movesets range as:
Swords Dance, Close Combat, Shadow sneak, Knock off
Swords Dance, Knock off, Close combat, ice Punch
Psycho cut, close combat, ice punch, knock off
Bulk up, drain punch, knock off, ice punch
Now depending on what set you run on Mega Gallade, you are walled by certain things. For example, Mega gallade without Psychic stab, can Be outstalled/walled by some poison types, such as mega Venusaur, and weezing. Those who lack Ice punch, tend do be walled by Gliscor, and Landorus. And if you manage to have all coverage moves at once without a boosting move, you cannot get the much needed atk boost you need to sweep with it, making it less threatening.
Final Thoughts: Gallade is a threat, but not enough to be suspected for
Mega Sableye:
As much as this Pokemon helps ghost, this thing has WAY too much support. sure fairy moves kill it, but guess what? Ghost has Aegislash. High specs powered water users such as keldeo sure. But guess what? Jellicent. Ok Kaiser your overreacting High power stab fire moves Hurt it alot. Sure it does, But chandeure comes to save the day. These Pokemon together, Make up a really Unbalanced Core. It just Makes Mega sableye too good on ghost then it does on dark. Also, with magic bounce, you can't even toxic it, para, or burn it. And with its amazing bulky and ability to burn. It can wall Your team both defensive and spD sides.
Final Thoughts: Mega Sableye should be banned on ghost
and dark.
Mega mawile ;_;:
Alright, as much as i hate this thing, I really believe it should only be type banned for steel monotype. Why? Because fairy JUst can't handle steel as well anymore. Just take a look at this replay
http://replay.pokemonshowdown.com/frost-monotype-1298378 without Mawile, I couldn't really beat my opponents bullet punch Metagross, and screens Only did so much. Now I know i can't use this as a valid argument, due to stuff like "ice can't deal with mega Scizor, what about that" Or "Mawile at +2 1HKO's 90% of our metagame" But i believe a type ban should be reconsidered. Gardevoir and Mega Diancie can handle steel to an extent, But they stand no Chance against a good core, and worst of all, steel type priority.
Final thoughts: Type Ban for Monosteel, Should stay on Mono fairy.