The surround plugin defines global mappings. Unfortunately, you can only override those with buffer-local ones, but not
:unmap them only in the buffer. Temporarily disabling and re-defining the global surround mappings would be possible, but is cumbersome.
I think the best solution would be patching the netrw plugin to add the
<nowait> argument to the
d mapping (and all other buffer-local plugin mappings). This would fix the timeout issue, and you probably don't need to invoke the other (surround et al.) mappings on a netrw buffer, anyway.
d mapping invokes a script-local function (
:call <SID>NetrwMakeDir("")), so it's difficult to redefine the mapping with an
:autocmd FileType netrw; you'd need the
<SID> of netrw. So please suggest that enhancement to netrw's author, Chip Campbell; you'll find his address in the script header.