Sure! Two examples where the Win32 API and/or my knowledge of it falls short,
* Layout management. There's no "easy" way of managing dialog layouts (letting controls expand/shrink on resize etc).
* Custom controls (e.g a tree-list-view) are clunky to write.
I'd much rather write PicoTorrent on top of the pure Win32 APIs, which I did in the beginning. It then evolved and when I valued time against frameworks, frameworks won, and saved me time :)You can hit me up at the email in my profile if you want to discuss further!