I think the current behavior is correct and desirable (as you say, it follows the order that would take place in an assignment, making it easy to roll-up existing for-loop code into a dict comprehension or to unroll and existing comprehension). Also, I think changing the behavior might risk introducing bugs into existing code that may have unconsciously relied on the existing order.  My recommendation is to document the current value-first behavior.

For the other issue, 11205, I agree with the discussion there that key-first-value-second makes more sense in the context of literals which are normally evaluated left-to-right.