I wouldn't know the details of each individual to really say directly. But rather look at this from individual game points of views and which aspects do the best and I wish were smashed together into one game:
Multiplayer team from iRacing and ACC
Physics from ACC
FFB from AC
VR support from iRacing
Graphics of ACC
Performance of AMS2
Sounds of ACC
Modding from AC
Content from AC
Best of the Race rules from iRacing and ACC and rFactor2
Not sure I want any existing penalty system
Free roam and some multiplayer aspects from Forza Horizons
Car mods from Gran Turismo
Career and single player experience from F1
Car Setup from PC2
Probably plenty more aspects but I think the ideal game is definitely a mix of the best of the various games out there, not all of them sims.
I'd want Stefano Casillo doing models.
Peter Boese doing weather and clouds.
Ilja doing shading and a whole host of other things.
Niels Heusinkveld and Renato Simioni doing physics