Not all parts of Win32 were designed equally well. File IO, process management and most of the threading primitivs have aged really well. Thread management hasn't. The GUI parts are a sometimes hacky mess because behavioral changes created mismatches between what functions were specified to do and what that gets actually translated to. Permissions are a pain in the butt with complex ACLs, transparent file access redirects and how process elevation works.
Yes, for sure. And with hindsight a lot of things would be done differently. I’m still really impressed by most of win32 given it was designed at a time where the software and hardware landscape looked so different from what we have today. Looks complex and messy at first but I learned a ton about what makes for good design by digging into win32 and NT