Completely agree, for small projects, or small patches of big projects, pull requests are not that bad, but neither very good IMHO as there is always a lot of background missing.
But the kind of pull requests I receive are often fairly large. New commands implemented or other large changes.
And there's the thing: not all patches are the same.
It's not even so much the size of the patch, but rather how much it gets into the design, I think. If someone sends a largish bugfix patch that doesn't touch design then that seems ok to me. Even if you don't like the actual patch, you'll probably do your own similar (but correct) patch.
But sending even a smallish patch that messes with design would have been better with discussion first. Even small tweaks to architecture, API/ABI, UX, etc. need careful consideration.
But the kind of pull requests I receive are often fairly large. New commands implemented or other large changes.