option createChildContextWithAs is false in default

[Auge19]

Hi!

our team migrated from ko to tko beta and got some issues in this progress. One was a "cannot bind to $parent" (don't remember to exact message right now). After some missleading error messages and debugging-time, we learned of the existence of the createChildContextWithAs option. That causes out problem, because the default is false and in the old behaviour it would be true.

So why is the default false? Totally fine, when it's for Performance! But was it a design decision?
Next question: Is there a more detailed migration guide. The readme and homepage seems quite outdated at some parts...