If this is to be Panasonic's final answer to the issue then I feel they have made a huge mistake which could cost them a considerable amount in lost sales due to lack of confidence in what has been until now a premium brand.
They have known about this issue for around 6 months now & despite initially publicly denying it I feel sure they have been looking into it behind the scenes.
I suspect but obviously can't prove that it is not going to be possible to fix this issue with a Firmware update & that either a replacement set or at very least significantly redesigned main-boards will be required. This of course could potentially become very expensive, the answer therefore; call it a feature!
As I have said in previous posts the logic behind increasing the plasma drive voltage is sound after several thousand hours (not 500 hours!) however this should not be at the expense of black levels & to say that they will settle after a few years is frankly BS, "Settle" at what level?
It is clear that a design fault has occurred as the 2010 models are reputedly going to be better in this respect
Given that only a relatively few sets are currently affected in the UK gives credence to a fault rather than a "Feature" otherwise every owner will become affected by this "Feature" at some stage.
We buy these sets in good faith based upon reviews & company marketing saying they produce exception PQ along with very black blacks which is why we pay a premium (in my case £1500 or $2360 for a 50V10) & we end up with a set which produces charcoal grey after 6 months of use, this can't be right & should not be deemed acceptable by anyone, we could buy a mid range LCD & get similar results & have a load of cash spare.
I do hope Panasonic give this more consideration & realise the potential damage this could do to their brand/Sales. We have all seen what is happening to Toyota by being in denial, something which may take decades to get customer confidence back in their brand. Of course no ones life is at risk with the Panasonic problem, however their reputation is! come on Panasonic, do the right thing!