I think what he’s referring to is “too few series” I.E we only get 3 daily races and there isn’t enough players to support more than that, which is definitely true.
If the regions were reduced to 2 or even just a global server like iRacing, we could have more events.
Total and utter disagreement. The Game as it is now is proof.
Sport Mode and GT League with online ability would lead completely separate lives just as Sport Mode and the Open Lobby does now. If anything, it's the open lobbies that will suffer. Open Lobbies will end up being more dedicated where as the folks that just want to have a good time will go to GT League.
As I said, Sport Mode would maintain it's purpose as a place to earn rank. GT League, as it is now, is focused on events rather than SR/DR. It would probably be for the best to have no DR/SR effect at all, as the lobbies do now. So, rather than starting up a lobby and inviting people to that, you would enter an event and either invite friends to your GT League event, or Join someone else's. An option for matchmaking could be a feature, or not. The lobbies have an option for minimum DR and SR so if you want strangers in your GT League event, you could simply activate that setting.
It's no different than the early days of Battlefield. You could have Huge 32 player matches or, if it was just you and a couple of friends, the handful of you would start a game and bots would fill the rest of the spaces. Those were completely separate entities that served specific purposes.
Edit: Actually, as I think about it more, the Sport Mode we know now could be completely eliminated. Simply have 1 race (not 1 event, just a single race) from each GT League tier be a ranked race. As I've said in the past, they'd need to clamp down on the freedom of tuning, but it would totally work. I'd even go so far as to have a weekly "Race D" which would come from the endurance events.
That approach would be better than the very repetitive events we have now.