GT does a lot of cool things but almost perfect is not a word that I would use. One key limitation that GT has is that it is a sim paid for by gamers. As such there will always be little aids to make things easier that can't be disabled (eg. there seams to be an autoblip and cars don't unsettle properly over curbs.) Some things are just hard to do on a console like a proper data logger and proper data analysis.
Well, can't argue with you there. I guess I'm coming to grips with this fact now.
But to backup my claim of "almost perfect", consider this. We all know racing isn't fun when you get a tool in the room driving the wrong way. iRacing solves this problem with software. They detect contact and assign blame universally. It's a non-optimum solution, but it works out in the long run because good drivers are able to avoid incidents, most of the time. The problem for me, however, is it changes the nature of the race. I found myself just trying to survive, being extremely defensive and celebrating when I finished a race on the lead lap, rather than when I won a race.
GT does not try to fix this problem. Instead, we have a community like this one that encourages clean driving through camaraderie and the spirit of the Tuna. And I enjoy that environment a lot more. Obviously, iRacing has similar communities. But they often choose a more authoritarian stance on these kinds of things that I find unappealing.
Combine that with a physics model that I think is overrated ... and a fixed racing schedule ... and well, if it were free I would consider it equal to GT. But if I have to pay for it? Who knows, I may go back someday, especially if they fix the physics simulation on the MX5. But GT6 would have to really get it wrong. We will see.