ProZD - Games that Think More Mechanics=More Fun

This isn't what "too many gameplay mechanics" is though: what he's describing is a game with too many core gameplay changes, or a game which tries to include too many genres. Game mechanics are basically the tools players are given to complete the game, while "core gameplay" is the medium you use these tools in, and it's really important to know the difference here 'cause I don't want people thinking that too many mechanics make a game bad, when it's the exact opposite, most times.
I don't see games which are damaged by having a ton of gameplay mechanics often, unless the devs over-extended and the game was buggier or had other undeveloped areas because of their one focus, or if a game forces them all on you at the same time and becomes over-complicated (which is only a problem for people who don't like that kind of gameplay style, you see it happen intentionally in simulator and strategy games all the time). People love that card games and fighting games have as many mechanics as possible (every critique I've seen with the MtG 2015 app says that it has too few cards, every critique I've seen of SFV says that it has too few characters) and if you imagine what a recent game you played would be like if it had less abilities, items, or characters, you get the picture: having a ton of mechanics gives a game a ton of replay value. I've even played games that had bugs and design problems which I kept playing 'cause they had so many things to play with, variety can save a game.

I thought it would be a critique on multiplayer FPS's that have so many different mechanics and ways to kill people that it becomes impossible to balance.

This works too