1. Host can ask the drivers to exit and kick anyone that refuses, right? But I can see a host abort being abused rather badly...
2. PD have never been that keen on letting people that didn't buy the unicorns drive them on someone else's dime. IIRC GT5 you could drive a DLC track you hadn't bought in an owners lobby, but GT6 nixed that.
3. Requires live background refresh of lap status. Currently, lobbies only refresh when you refresh the page. But even with that limitation, it would be an improvement.
4. Or least popular!