What makes you call it a “heap of shyt”
Bad PC Port. Performance was and still is terrible as much as I know.
Rushed bi-yearly release that downgraded things like GFX (which hide behind cloudy weather to mute the otherwise dynamic visuals) and engine audio.
Homologation issues for races. I understand this a little more to keep old cars from getting busted and OP from upgrades, but it strangles the variety and progression of an individual car. Also some issues with solely visual customization and rating limits.
I don't like the progression as much as 6, and that system is super bland.
Driveatar AI is still busted. This is coupled with the juiced AI at higher levels (ex. better accel, more grip) that has certain cars just take a 5s lead after lap 1. If they utilized the driving data properly, you wouldn't need extra juicing as you'd have comparatively similar race results for your difficulty.
Downgraded presentation in the menus. As personal as this one is, I don't know who thought cornfield tractor rock in the warehouse was good, but the classic strings of 6 and the Xbox Metro layout is far, far superior.
All that without mentioning the loot infused system and MTX pocket picking. Pretty sure most would agree 6 is the best of the last three.
Turn 10 looked in the mirror after this release and realized it was garbage. Now, Forza 8 might be good since they're taking their time.