I'm all for them expanding the rogues gallery if they think they can revitalize a weak villain like TAS did with Mr. Freeze in "Heart of Ice", but to actively avoid using the main rogues gallery seems like a mistake. They're popular because they are so very effective as villains.
I think the writers see potential with these villains as the next Freeze. Anarky and Pyg especially imo were created with the potential to be the next Joker/Two-Face/Ra's, but with their potential never readily utilized.