The issue with having an option for sellers to remove requests is that it is actually in those sellers interests to remove legitimate requests AFTER they respond. For example:
I am looking through buyer requests and see a job I want to do. I respond to the request and afterwards I remove it so nobody else can respond. To stop this, we would need staff to oversee it which would beg the question why staff couldn’t just moderate them in the first place.
I like the idea of sellers of a certain trust criteria but that would not stop the potential for abusing the power.
My preference would be for there to be staff who do it instead. It would not take more than 1 person part-time to do it for all categories. I offer services in 4 categories and rarely see more than 20-30 per day. It takes me 2 minutes to scan them and click to remove the rubbish. It really isnt a big job.
The cost of the staff member would be offset by the fact that the Buyer Request section would actually become useful again. This method of posting jobs is the way MOST BUYERS are familiar with as other sites do this as their main method. I sometimes see requests from bigger businesses and seriously professional people and I shudder when I think what kind of rubbish responses they will get - what must they think of the platform in this case?
By cleaning up and improving buyer requests, many higher quality and higher level sellers would begin visiting it again and that can only be good for Buyers and the whole Fiverr platform.
Edit: It could also be done by paying one or two trusted sellers $5 each to check the requests on a given day. At most it is 20-30 mins work.