Icon-only navigation is not what Flanders did mean with his Mystery meat navigation. I think you had there some valid points, but for most of it, I don’t really agree with you.
For example those back, home & recent apps -icons are constantly used and perfectly known and understood after the first try. And since they are distinct icons (and not mystery meat blobs of different colors or such), and they are reasonably / semantically positioned (“<” (back) is on left, as back is traditionally and “O” (home screen) is centered, as the home button has been since the first iPhone & Android, as it’s the most important position).
I also disagree with + button being mystery meat at all. The context where you are should tell you exactly what the + is going to do, and if not, you have other problems with your app than mystery meat navigation…
In short, I think it’s perfectly OK to use only icons for 10 or so of the most common features you use on your phone, since you are using them daily. A totally different thing than some random web sites using just numbers or colorful circles for navigation so that you really cannot grasp what kind of meat, beef or pork you’ll get without hovering over the link.