Great writeup, it pretty much reflects my views as well. One caveat, I don't believe twig is being ported over, but they're thinking of writing something similar.
Whats worse is that it won't be compatible with Drupal at all, so they're pretty much making a new CMS based on bad industry practices. These were ingenious hacks when PHP 3 was out, but that was over 10 years ago. The idea of turning the clock back is bad.
The FUD that backdrop spreads is toxic to the greater Drupal community and helps re-enforce why external people don't like drupal in the first place. My hope is that instead of people flocking to backdrop, they will learn new programming constructs and become better programmers.