The content is too difficult for the average player. It's the same reason why an extreme trial or savage content roulette does not exist.

The average player will not understand or care to understand mechs or any other map mechanics. It would not be enjoyable for anyone. People will just do it for quick rewards. We already have a lot of people AFK in frontlines, RW is worst because it's smaller scale.

Better ways to get more people playing would be new rewards, new map or bring back old map. Fun achievements could be cool too, "Destroy 100 Oppressors" and so forth.