I think a lot of this is situational and comes with having to read the people who are in the server. A lot of people (and captains) choose maps that I know instantly would result in garbage games based on the players in the server. Not inherently because they might be bad players, but because they simply can't play the maps due to refusal to think. And that results in taking the safe route of a map that everyone can play, ala Frostbyte.
Great, let's play Stygian even though we have 17 in TS. Let's play Core, even though only 2 people can run a non-front route. Let's play Zenith, even though based on the player composition in TS, the LO are not very good and the home Ds are top-notch. You simply know it's going to be a bad game, and I don't have much desire to spend 30 mins picking teams and starting a map, and then playing 25 mins of boring, and I think few others do as well.
Another item is that the maps will inevitably evolve (or devolve) into a certain rotation (it happened in T1, same complaints, same 3-4 maps - dx, sh, hb, rd), but that also meant that there was no worry about whether certain maps would get played, or maps within rotation would get overplayed, and they each had their characteristic strategies. Do I have any desire to play Mirage even though I've never played it in a pu? No. It's a bad map, a bad base, and I have no intention of learning any routes beyond the 4 I can do (3 of BugsPray's).
My suggestions: completely get rid of moonshine from everywhere, and mirage can have a token server where it's run.
Regular pu maps would likely be: Small numbers (5's, 6's): Nivosus, Stygian, Frostbyte, Medium numbers (7's-8's): Fb, Zen, Fall, Elegiac, Gorge, Big numbers (8 and beyond): Blade, Zen, Fall, Elegiac, Core
That covers every map except Mirage I think. Having played in Euro, US, and Asian Pugs - small numbers are way underplayed (I actually like 5v5 very much), Elegiac needs more love, and frostbyte needs to pull back a bit. The rest are getting their due I think.
It depends what the objection by the dev is - personal or communal. Just because you're captain doesn't mean you arbitrarily get to choose a map that 80% don't want to play.