4 year lurker, new account. Mega Kanga has made me quit playing Pokebank OU and OU on the sim, as well as making me quit in game Wifi Battling. As someone who loves using gimmicks, NU Pokemon, and alternate strategies such as TR in OU, Mega Kanga has made it impossible to do that. If you don't put at least two Pokemon on your team who are 100% dedicated to Mega Kanga, it sweeps you. And even Pokemon dedicated to checking Mega Kanga, are simply semi-reliable checks and not counters. The two prime examples people like to point to are Rockey Helmet Ferrothorn and Prankster WoW Sableye. Might I remind you that after Pokebank is released, Kanga gains access to Fire Punch for a clean OHKO, and Drain Punch to restore all the health that it has lost from Iron Barbs + Rocky Helmet. And for Sableye, take a look at this.
+2 252+ Atk Mega Kangaskhan Crunch vs. 0 HP / 0 Def Sableye: 236-278 (97.9 - 115.3%) -- 87.5% chance to OHKO This means that Sableye cannot switch in on Mega Kanga, hence something has to be foddered in order to get the burn onto Mega Kanga. As well, after the WoW Burn, which don't forget has a high chance of missing, it's still a 95% chance to 2HKO with Crunch. This means that Sableye has to run Recover in order to be useful against Mega Kanga, it has to run 2 specific moves in order to be ALMOST useful, seeing as Burn can be healed easily from Heal Bell, Aromatherapy, and other such moves. Now do you see what I'm talking about when I say Mega Kanga kills a teams creativity and limits player's ability to have fun in the current meta?
Also: Screenie of me reaching the 1900's as proof I am no noob.
Proof of ladder rating:
http://prntscr.com/20dgrk
EDIT: Forgot about EQ, which does not make contact ergo negating Mummy, Iron Barbs, Flame Body, and Rocky Helmet.