the problem with introducing new maps in pugs is the fluctuation between players who have never played it to players who know it very well. It creates a bad learning environment and even worse way to test new maps.
It's similar to why gpit is a bad pug map: team coordination and know-how just isn't strong enough for the pug to be playable (for obvious reasons)
MAYBE/hopefully a dedicated 'new map pug' system will help this but in my opinion the best way to test new maps is with two teams.