I find it funny how you made a petition and not a vote, just to hide the fact that not everyone likes greninja.
Also, the issue with greninja isn't the fact people like it or not. It's that it's way too unhealthy. Yes, it is frail and it got a 4-move syndrom, but that's not enough to make it balanced. Frail? It's a revenge killer able to revenge kill most of the metagame, with a crazy 122 speed and a fairly good attack stat. 4-slots syndrom? It already got 4 STABs, not 4 moves, but 4 STABs all with different typings. The oppenent has no way to know what you're playing (except maybe U-turn), and having the STAB provide you more power than it would normal have: a hidden power fire STAB is the same as a flamethrower non-stab, just imagine.
It got no real switch-in, only checks. While it should be a good way to beat offenses, it became able to beat all styles with some coverage. Clefable? Gunk Shot. Chansey? Low kick. Ferrothorn? HP fire and low kick. Heatran? Low kick and HPump. Tyranitar? Low kick. Alomomola? HP grass
It puts so much pressure because the oppenent doesn't know what moves it carries, which means greninja is creating momentum like a mad man by provoking switches. It gives it lots of free turns to put spikes on and even toxic spikes.
It's not because it was here for 2 years that it was balanced, it's that people got attached to it or enjoyed selling it for crazy prices, but that has nothing to do in PVP. Even if you compare with Smogon, PRO is mostly gen 6 ORAS, and Gren got banned at the very beggining of ORAS. Guess what, it was because of Low kick and Gunk Shot being added to its movepool. And guess what, these moves are available on PRO too.
I don't like Mega-Metagross either, but the comparaison is way too far-fetched.