Watch directories is the big one.

Virtually every other music manager supports watch directories. Its omission from iTunes isn't due to them overlooking the feature. Rather, it's a coercive measure to try and push users towards acquiring all their new music through the iTunes Music Store.

It becomes the "path of least resistance" when you intentionally omit features to make all other paths harder.

That's quite a theory. Wouldn't one expect to find other instances of such coercive omission? And yet, double-clicking a file in the Finder or Explorer still opens it in iTunes, which by default copies the track into your library. Ripping CDs still works the same. Drag and drop still works the same.

No, I think it has more to do with watch folders not being a feature in high demand than any conspiratorial nonsense.

If watch folders are very important to you you might look at Hazel (http://www.noodlesoft.com/hazel.php), which is like a more tolerable implementation of Folder Actions. It has a "Import into iTunes" action built in, and can be set to recurse subfolders. If iTunes is set to copy files on import, Hazel can be told to trash the original.

I wouldn't recommend it for just that, but even if it doesn't strike your fancy--after the trial expires, it still works on one folder with two rules (e.g. Add to iTunes & Move to Trash), so it doesn't really cost anything if that's all you use it for.

I'm not excusing the lack of a similar feature in iTunes, but that's what I use and I'm happy with it.