much of what you said sounds positive to a sane person, but to me, this is the problem...things glommed on to other things and this comes from this and that comes from there and if you take your ear off the ground you will miss this update/module/python script/workaround/future thing/patch/hack that does what it should've done last release.  Not only do we have to find out about a different renderer, but we need to find out about the bridge to that renderer, arg. 

As for backwards compatibility, with the right focus on developments nobody would want to look backwards.

I've lost all my stuff no less than four times over the years.  Once you confront the horror and process it, it's kind of nice to have a fresh start.