If you didn't play MoP and WoD, then maybe it's really new for you, but Mythic+ is nothing more than rebranded challenge mode. Multiple difficulties instead of one, scaling mobs up instead of scaling party down, chests instead of medals and imbalanced affixes — that's all. I'd argue that CM was more challenging, because you couldn't just roflstomp it with better gear, like people do with M+15 right now.
So we have rebranded dailies, rebranded CM and rebranded warforged, so where's your 'more content than ever'?