Just another vote for your idea.
Could at least PFS bandwidth/slots (the sharing of incomplete file chunks) be halved to give room for other uploads with fewer alternate locations?
I wonder if allocating dynamic bandwidth "pipes" to folders might be a way to help the large/small file problem. Shared folders could be dragged in the Library up or down a priority queue, a bit like the one used in the downloads panel.
Folder class A-- 60% pipe of available upload bandwith. When unused, the bw fattens the pipes of the other classes
Class B--30% pipe
Class C (incomplete)--10% pipe
sigh. Wish I learned to code