Tell me Mark, how long time has it been since you bought a game that did not get patched after release, AND that did not contain bugs? I count it in years.
As to the acceptability, there are some bugs in the game that are not acceptable, and should have been picked up by the testers. But it is not many that have gamewrecking ramifications. I count
1) Where is my front right wheel?
2) Mechanics won't let me go from the pits.
3) Problems for the AI, when trying to enter the pits at Nürburgring and Sepang, and possibly other tracks (have not heard of it yet tho).
4) Mechanical failure spoiler bug. If the car, from which your point of view starts, when you enter the track, is going to have a mechanical failure, then the left yellow led on the steering wheel is constantly lit on all cars. If you enter in a car that is not going to have a failure, no yellow leds are prematurely lit. This looks like a beta-test feature, that is incorrectly disabled. It would be nice to know if a car is going to break down in the beta phase, as it can be monitored during testing.
The rest of the bugs are minor. Some are annoying, like marshalls that forget to back to their posts behind the fences and the cars dissappear at long range in heat haze. Some are very minor as a incorrect popup helptext over the Traction control aid, and the broken 2 pitstop buttons (which do work, just not like they are supposed to). 4 game threating bugs seem to me to be somewhere between average and better than average, considering the state most games are in when they are released. The important thing is not really that there are bugs.
The important things is whether or not they are fixed, and how long this takes.
It's only after we've lost everything, that we are free to do anything.