> I’d like it to be easier to use those libraries in a non-async context (e.g. by bringing a pollster-like API into the standard library),

I think this would simultaneously solve two of the major gripes expressed here and elsewhere.

1) An easy answer for those who wish to avoid being sucked into async just because there's a useful crate that has async.

2) Blessing an executor other than tokio avoids tokio lock in.