There are a lots of complaints from kernel developers when someone dumps a whole lot of code on the kernel for merging (new filesystem, driver, etc.). The kernel people usually say that these developers should have worked with them from the point of typing the first line of the new code.
Of course, if development starts in the open, there is a push to merge it early to the mainline (so if someone changes yet an other internal API, the code will be automatically updated). However, code released early tend to contain lots of bugs that could be easily fixed - hence there's a contant flow of small fixes and new features and I guess is hard to stop this flow.
So I this problem is inherent in the current development process.