Well, problem is that we don't know all the facts yet IMO.
I do agree with you though; it seems as if Apple stores make no fuss what so ever about replacing the device. But I think its also too early to conclude that the problems aren't as huge as some people claim.
After all; we should never forget that not every story about issues will hit the Net. A lot of people use tablets for their own needs (e-mail, surfing, video's, etc.) because its easy, it suits them and its all not too technical. Do you really think such people would look up technical fora ?
Then there's the number of people who may have merely noticed something going wrong and then went back to the store to either replace or refund the device and (hopefully) that was the end of it. I don't think you'll hear much from those people either (esp. not if they fall within the range of people I mentioned above).
Not everyone will make themselves heard on the Net.
IMO we wouldn't have heard about this at all if it actually were a non-issue which was taken out of proportions.
Finally.. Yes, there is always a margin for errors. But a lot of cases which have the /exact/ same failure? That doesn't compute. Sure; some devices will b0rk, others may act weird, that stuff happens, totally agreed. But IMO it gets different when such devices all share a same problem.