More patience? Generally speaking, I would agree with your statement and the idea behind it, but this situation was not one remedied by patience, nor was it created by lack of patience.
The evening that I posted my comment (above) I spent several hours reviewing all the various threads regarding this same problem, its similar manifestation on various devices, apparently experienced by many people over the last several years, most of which remained unresolved. All the while I was reading these complaints, my own iPhone was stuck on step 5 of 5, Waiting For Changes to be Applied. My iPhone sat in that 'stalled' state for at least three hours before I finally pulled the plug. Had I not, I might still be waiting. I was not syncing my music library (I subscribe to Match), nor was I syncing photos. There were some updated apps, not many, and most I don't even sync to my iPhone. Basically, I was simply trying to sync some new ringtones. That should not take three+ hours. Or longer.
That said, apparently the latest version of iTunes which I installed the following day--yesterday (with no small amount of trepidation because the previous update had major problems, resulting in a failed installation which required the removal of every single component of the program, along with some other 'through-hoops-jumping,' before being able to do a clean install, this all being very time consuming), has resolved the problem. For me, anyway. The syncing of my iPhone is working well again. Like it should.
I doubt I'll ever be a fan of iTunes. I am sick & tired of the constant updates to it, too; they seem to come weekly now. But I'm obviously tied into it until such time I return to the Windows environment and then I'll have to redo everything, which I did many years ago when I converted from Windows to Apple. That is not likely to happen any time soon, given the number of Apple devices I own, and like. They are very good products, all considered. It's too bad iTunes can't be as good a program as the devices it serves to support.