Problem? Yes. Cover up? Maybe.
From what I read in the Anandtech review it seems that the bars are so heavily weighted towards one end that a small signal drop will display as a massive loss in 'bars'.
The scale goes from -113 to -51, so it has a range of 62 units. The problem is that bar 5 is range -91 to -51 (40 units) and bars 1-4 are range -113 to -91 (22 units). This means that if you currently have a signal of -90 (only just 5 bars) and you drop 20dB (roughly what is lost when using the 'death grip'), you may have lost around 1/3 of the possible signal, but the bars will show a drop from 5 bars to 1 bar (bar 1 is range -113 to -107). You would have a signal of -111dB which as Anandtech points out, is actually usable on the iPhone 4.
The problem is that the iPhone 4 is more susceptible to signal attenuation than most phones (as pointed out by Anandtech), so when you couple this with the weird 'bars' scale the problem appears far worse than it is.
Yes, there is a genuine problem with the iPhone 4 that at first glance could be easily fixed with a coating over the antenna. A lot of people online are complaining about dropped calls, which is a big issue, however I also think that a lot of people are making noise about lost 'bars', which may not be as bad as it seems.
Are Apple maliciously trying to cover up the problem, or do they genuinely believe the issue is signal display and not strength? Personally I think it's a little of both. I'm sure they are aware that their antenna design is more susceptible to signal attenuation than most other phones, however I think they have made a rod for their own back with the dumb scale they used to display signal strength. I also think that with the more sensitive baseband hardware in the iPhone 4 (again, as attested by Anandtech) Apple may well believe that the phone can still outperform others in real world usage, even with lower signal numbers.
Perhaps the software update will weed out all those complaining about bars dropping rather than calls dropping. Although I'm sure they will just moan that they used to have a 5 bar signal when sat in Starbucks and now only have 4.
It will be interesting to see how Apple responds after this update is released and after someone undertakes some serious research into the issue. I will reserve my judgement of the company until then, although they are going to have to tread carefully. Personally I feel they should recall and replace with a version that has a coated antenna. Costly yes, but probably less pricey than the hit to their credibility for not doing it.