caucatc
The "C" in "ATC" stands for Control. You control the traffic and the pilot flies the aeroplane. If you let the pilots dictate which runway they want then you are creating problems for the future......as well as a potential for unsafe or dangerous traffic situations. No problem when quiet, but they expect the same service even when you are too busy. It requires a disciplined attitude and compliance with the normal operating procedures once you have decided which is going to be your designated runway[s].
Sometimes the pilots will benefit....other times not.
ATC are always prepared to make an extra effort for a particular request.....and if you have any problem may I suggest..."that runway will be available but expect a 20 minute delay due other traffic!"