This is a great post. It goes into much more back end detail than I ever could, but mirrors my disappointment with the changes.
Essentially I'm still running Legacy app as long as I can. It's many times faster, and it searches while I type, has never (or very rarely) ever has a sync issue. All of which, have gone out the window with the new version.
The main reason I have used Evernote for 10 years is I could very quickly, browse, search, view and switch between notes very quickly. Since going to the new version sync collisions are plentiful and speed makes it unusable. I finally went back to the Legacy edition.