The basic gameplay loop and mechanics of the game were sound. The looter shooter aspect and balancing issues seemed to be a big issue for folks, and once public opinion turned on the game it never recovered. I think the bones of the game would make a great foundation for another game. Perhaps use some of the business practices (minus bugs) from Arrowhead Studios and the Helldivers 2 team to make a better game (not a looter shooter).
Overall, amazing game, great potential. Shame it was so short lived and didn't have the opportunity to fix it's issues or adjust fire and develop into the legend it could have been.