Well, I can't say physics will make me jump ship (simply because FM1 had physics on the side of NFS more than anything else).
That said, although visual improvements are important to me, I would rather have all upgrades make a difference in gameplay (cough brakes cough).
Of course, even if there are no changes I will not be jumping ship too easily. Even though Forza provides visual upgrades for some of the Japanese cars, it's the tracks in Forza that concern me.
Plain and simple (as I've said before), if all things remain the same, but Forza gets track replication correct, then I will switch.
However, if Forza gets the Nurburgring wrong again there will be no contest. I just can't give up the amazing accuracy of GT for the sake of getting visual mods.
I'd rather have GT's tracks than Forza's mods.
Of course, if Forza gets the tracks right it might end up being a no-contest situation.
Btw, I don't like the idea of fuel and tire wear playing a part in Free Run... That would ruin GT mode for many people and cause a massive migration to arcade mode for time trials.
Plus, if you really want that simulation Free Run feel then do the Track Day Events... They give you other cars on the track and all of the simulation elements like tire wear and fuel consumption.
Oh and that reminds me... I would like to see pit stop changes for settings. 👍
It would be really nice to make a slightly extended pitstop as to adjust settings.