Way better career mode than gt5/gt6. I predict gt7 career mode will be pretty massive.
250 new cars
I say like MAYBE 25-30 standard cars get upgraded to full premium.
Standard cars will get upgraded but interior view for those cars will not be available. Like there won't be no black out interior either like how it was in gt5/gt6. So standards will look great when it comes to outside appearance but those cars still won't have interior views.
AI will be slightly better
Sound will be a major improvement
Damage will be improved but still meh.
24 cars offline and online will be 16 of course
Livery editor, it won't be impressive but it will be basic. Simple to use.
Manufacturer races (that gt4 had) will return. Every manufacturer will have races available.
10-15 new tracks. (10 will be real life circuits while the other 5 will be fantasy tracks. Maybe a return track from gt3 or gt4.
Online will receive a lot of things and improvements.
Shuffle racing will return.......hopefully!(please kaz)
Photo mode will receive new things and improvements along with way more photo mode locations.
And last great lounge music in the main menu of course like every gran turismo
That's my prediction for gt7.

And hopefully all the main features will be in the game at release this time.