In tight shops where sales sits next to engineers and personal relationships are built, those small issues tend to get resolved rather quickly, leading to happier parties on both end, happier customers and higher product quality.
In distributed shops request must flow through a gatekeeper, such as project manager, who then keeps and prioritizes a list of such requests. Sales people then complain that nothing ever gets done, and requests go into a vacuum, while engineers complain about too much bureaucracy and inability to concentrate on large projects with all the pesky requests streaming in.
Why not a web forum or a chatroom? Some chat software even allows screen sharing.
Even though we are literally across the street from each other, and even though we are together with like co-workers and departments, we've felt the same issue you've described here.
This is because we have grown lately and expanding our physical space has been... a complicated procedure. I'll be glad when we've moved into a single office again, which should happen by the end of the year.