First of all, kudos, Varnish is an amazing piece of kit and hat's off to you sir.
However, I've been where you are and know how you feel, what you've said makes perfect logical sense to you, in your mind these are clear instructions on what should be done, but they still mean very little to someone who's completely new to this (even though they've been using Varnish for a good while now).
I'm a WordPress dev (I know, but it pays the bills), but I have been put between a rock and a hard place, so now I'm also responsible for setting up DO droplets for standalone websites. The reason I use Varnish is simplicity: apt-get install, wget on a WordPress vcl file, change a port and we're saving ram and can serve to 6x-10x concurrent users than before on straight nginx.
Thing is, I'm not alone in this use case, I know several people, who adore the magic and ease of use of Varnish. None of us know the insides, but we're can copy-paste and change a few things.
We respect and understand the need for dropping backwards compatibility, but all believe that the upgrade docs desperately need some examples.
I know it's the language of the devil, but the docs and the examples are definitely very usable to complete newbies:
http://php.net/manual/en/function.date.php
Your docs are great for someone who has the time to read them all and learn all about Varnish, like a book, but (with no disrespect) borderline useless to someone who's got deadlines and a ton of work and simply has no time to learn this system that he's been relying on for a while.