Add more scenes like :
Drag Racing- having trailers to haul the cars, legal and illegal drag locations. Having the ability to have more detailed car upgrades like being able to build your engine, swaps etc.
Drifts- Having some drift tracks, also the ability to have better upgrades like engine building, tires etc.
Rally- Have some off-road spots to have rally races like in sandy or paleto area.
Better customization for cars in general with being able to build engines, swaps. Fix being able to switch rims for some cars which you cant. Also able to add camber (When you have a widebody car it doesn't allow you to keep stock rim camber so it looks odd). A selection of imported rims. Bring some sort of in depth tuning with maybe the need of a dyno, different gas types with different prices.