That is something i do not understand. People have pretty good rigs and get frame rates like a 3 year old computer. I guess people should invest more time in setting up their system. I know not everybody is a computer expert, but seriously, it is not rocket science. Get rid off all the software and services you do not need, get decent drivers, don't play at resolutions or with settings your computer can't handle.
I can understand that people get frustrated when their PC can't handle large servers, but that is no reason to lower the limit back to 32 and while doing that, take away the fun other people have.
If you know your machine can't handle the game with 50 players, stick to the 32 player servers.