Not really. As 9_6 said, it could make the lower-end PCs struggle with KF.
The idea behind having it a server-side option was so that people can make it harder for those that can handle it, without making the PCs that can only run KF as it is now unable to play at all.
Of course if the increase is substantial it can happen but the increase doesn't have to be that great. Testing would be done to figure out a good amount. If even a small amount causes the game to become unplayable for someone it was already almost unplayable. But as I said server side probably works too.
Tbh it could just be 32 is a nice balance. If you start upping it to 48 or 72 then waves are going to be over pretty quickly and realistically the only way to win against that number of specimens is to use perks focused more on killing large numbers of specimens. You'd just turn everyone into Firebug Flamethrower sweepers or AA12 Support Specs with maybe 1 SS and Zerker for Scrakes and FPs.
Isn't it possible to do this using Sandbox mode anyway? Can't you fire up a server with that if you and your friends want a challenge? I can only assume you wouldn't be interested in perk progression.
You are right that sweepers become too important if you increase the amount a lot but we don't need to go that far. Though when you really think about it most perks are good at sweeping. One of the best being ss ironically enough.
You can indeed try it in sandbox and I have done so. It worked very well for the group I play with. I believe it would work well for normal servers too. We don't use sandbox often though because most of us want to level perks.
