Q:  
What do these three recently well-received Meta posts have in common?
Change “unanswered”
search to “unsolved”
Should we have a meta-sorted list of
puzzles here on Meta?
Should we implement an automated way of highlighting
quality content?
Hint, but basically the answer:
Ready access, including for newcomers, to Puzzling posts that meet useful nonstandard criteria.
Q:  
How do we get Stack Exchange developers
to help us improve the site's interface?
$\color{#3c3}{\Large\checkmark\kern-4mu}$A:   We don't. They are busy rushing to accidents and don't have time for traffic snarls.
Q:  
What can we do?
A:   We can easily add a single always-featured Meta post that shows up near the standard search options. This is prime interface real estate, completely under our control, and may be used for more than what is presented here. The posts mentioned above could be well served by having the title of such an ever-present post include something like “unsolved | other searches | curated.”
Clicking there would go to something like the following. (Plagiarized from posts mentioned above.)
Automated searches
Puzzles you may have missed, 2016/01
Well received puzzles, 2016/01
Curated categories
Puzzles that require a lot of work to solve
Puzzles that are good to use in RPG adventures
$~\raise-1ex\vdots$