I understand the hesitation to request a new crawl of a given website, but there are circumstances where this is very important and I have a proposal.
Some examples include: having new content on existing URLs that is vital to a given service, having a bunch of new content or products that are vital to a service and submitting single URLs is not an option due to the daily limit, or in my case, I need to add "seach." meta tags to complete my project and now it looks like I will have to wait weeks and can't even test until then.
I understand the issue is the nature of maintaining an Internet wide search and the algorithms to prioritize bot resources. However, what if it was a paid service to ask for a re-crawl and this would deincentize overuse and possibly generate some revenue for MS.