The impression I'm getting is that rather than sacking off the campaign mode in favour of multiplayer the team have merged them with Sport mode - the AI has essentially been replaced with actual real-world players, making it something more akin to a MMO, but not?
Honestly, I can understand the disappointment, but, for better or worse, I think PD are trying to evolve the series and I can't fault them for that - they've done six iterations on the formula that launched the franchise. Looking for meaningful ways to progress the racing genre beyond prettier graphics is a bold - and potentionally dangerous - move.
It's caught them a lot more flak than simply reskinning GT6 and adding some upgraded visuals would have done and I'm tempted to believe that it's because they want to keep moving forward then just doing a new variant of the same circuit... maybe I'm wrong, but I think it'd be a mistake to dismiss it out of hand.