It should be, since they (& we) call it driving simulator. And the feel of realistic is one of the major reasons we love this game, isn't it?
And I don't think the tire noise is that exaggerated. Compared to the previous GTs, yes the screaming is somewhat sharper and louder. But if we drive a real car spiritually with the windows rolled down, then I'd say the noises are pretty close.
OTOH, slightly more pronounced tire sounds in the game are actually a very good indication to the grip of four corners. It's a wonderful tool when driving without aids (TCS & ABS). In general, I prefer it over those exhaust drone in some cars.
However, strong FFB on low grip conditions is unreal & unreasonable. I can't find a positive reason for it, so I consider it a bug.