The first few laps would be a little slower and more cautious as they warmed up their tyres, but after that things would be normal. And remember, F1 drivers are supposed to be the best that there are 
That's ONE of the concerns: the differential speed between a driver on fumes lapping at track record speed and some back marker coming out of the pits with a full tank and cold tires. They will drive even slower with cold tires (as opposed to heated ones until now).
However, when it comes round to the guy running on fumes putting on new tyres in the pits, the balance is restored as they also have to make the slow lap.
Did you read my posts? I don't care about the balance. It's about the dangerous speed differential that will be greater than without blankets and it's about instability of the car which may trigger some accident.
And on top of that - the backmarkers are more likely to run a one-stop strategy, thus losing time only once, while the front runners (partly due to q3) will likely have one or two more stops, thus losing more time. That's what I was referring to with respect to Honda - they would prefer such a scenario to level the playing field.
I read your post. And I also made a point earlier about traction control and engine braking. A driver could be trying an overtaking move going into a corner, brake too late (using a braking point that would have been fine if the car had engine braking) and smash into the other car, possibly injuring one or more driver. Are you saying that, because of that risk, the driver aids should be reinstated?
I'm not sure it would level the playing field that much, considering next year's regulations. We could see any team have the best car, because of the huge changes. Thus Honda may see themselves with a car like the 2004 BAR and be scoring many more points. That's what they are hoping for, so it would be silly to back something with the intention of making it easier for a slower team when they are trying to move forward in terms of speed.
And finally, if slick tyres do return next season, this would be less of a problem than it would be for grooved tyres, since slicks have a much greater area in contact with the track, allowing the tyre to heat up quicker.