it's likely more than 4 we're talking about.
I don't think so. When I run an event, if there is something to complain about, I get complained at. I do think out of about 500 players, about 1% have any issue that they blame on clouds. And out of them, probably about half are not having an issue with clouds per se but don't know what they are doing to adjust any graphics settings at all, and the other half have some frame-rate hit because they are playing on ancient hardware.
The difference is that I'm using fairly light to moderate clouds in events of particular cloud types that don't seem to have much impact.
Also, 1% complaint rate for special events is not a significant amount of complaining. I get more complaints than that about any particular aspect ("the ships are too far away", "the ships are too close", "there are too many of plane X", "there are too few of plane X", "plane Y isn't a good substitute for plane Z, so your event is crap", etc.) than I ever did about clouds causing frame-rate issues.