Denied for now.
We already have minimum FPS limit of 20( we got to take count of players with FPS limit of 30 ) so if your FPS stays below the limit for more than few second then you will be kicked.
Besides, majority of players do face the FPS drop some times and the built-in function to get player's FPS value isnt updated frequently( change once per few seconds ). If we force stricter control, it might affect more players and i think it's not suitable for public 'everyday' server that you can choose with whom you want to fight, not a tournament.