Well, as i said it will likely get abused to kick player that face temporary FPS drop or ping spike even they are not fighting or in cases in which it only happens for few sec that won't affect the game. But as FPS and ping value is updated at specific intervals, the value stay the same for few more second. That's why we add delay in the detector to calculate the average. Besides FPS and ping, packet loss, etc also cause issue.. Low ping doesn't always mean your game is smooth.
About adding more and more limit with reason players should own..blababla in 2018, it doesn't change the fact that there are many more players playing in low end pc or having higher ping. The VCMP player count is not high and the amount of new player that enter VCMP is very low. The more limit we add, the more players that are left in VCMP being disallowed from playing. So, it's between playing with same few players which will eventually getting lesser and lesser as they leave or face a little lag with more players than the first option.