The worst thing about developing from my POV isn't something that actually affects core developers so much, namely the lack of a nice MSVC equivalent of PGXS.
I completely agree there. I wrote some documentation on how to make project files to build extensions, but it'd be nice to *generate* them instead, like we do for in-tree builds.
The problem is that we don't install all the Perl build stuff on Windows, it's only in the build tree. The time consuming part wx is / sll be cleaning that up so it can run outside src/tools/msvc, getting it to use pg_config, and making it installable. Then of course there's the issue that it won't be available before 9.7 at the soonest... unless some brave soul backports it as an installable add-on. Which means extension authors are still screwed for 5+ years. That's the main reason I haven't tackled it - so far I've got by pretty well with VS project files + property sheets, and any PGXS-like capability almost certainly couldn't be backported so it's nearly useless for about 5 years.