They canceled the GTA V story DLC after seeing the success of GTA Online, and their long-time head writer and producer resigned. I have little faith that GTA6 will capture the same spark that their earlier games had.
Mine are hopeful. I expect GTA Online to still be shit, but I hope that the main story is good. Considering it's rockstar, then it should be a pretty proper game story wise. But we'll just have to wait and see.