The usual case is that the QA/QC procedure results in a new, improved dataset -- exactly what happened with the GHCN v2. This is how the scientists maintain their credibility. If others think that there is still bad data in the dataset, then they have to demonstrate that the effect of the bad data is significant.
Your second paragraph indicates that you "know" the conclusion without any knowledge of the depth of the problems with the methods and data collection errors. This too is bad science. Some would even call your position "faith"
Anybody who thought that would be an idiot. My statement is an evaluation of the entire body of the science. I may write more on this later -- I have several ideas floating around in my head. I have a question for you: do you think that problems with surface station data may be significant enough to eliminate the 0.6 C warming of the 20th century and the 0.4 C warming since the 1980s?
No. It isn't. You place a lot of emphasis on peer review. Why aren't the methods of data correction released for peer review? Scientists maintain credibility by working with a high degree of tranparency. Bad data happens, QA errors happen...but when they do, it is the obligation of the scientist to be open to scrutiny rather than the secrecy here.
I have a question for you: do you think that problems with surface station data may be significant enough to eliminate the 0.6 C warming of the 20th century and the 0.4 C warming since the 1980s?
I haven't the slightest idea. However, I looked at the station audit site and found that a significant number of the stations had BLATENT temperature collection problems. I suspect the problem is worse in other countries where QA is even looser.
Bad data happens. When it does happen, a proper scientist would either provide his justification for using the data, and openly provide his methodology and basis for a correction, or reject the data outright. Frankly, I'm more alarmed at the secrecy in which data correction is performed than I am with the QA slip-ups. I'm at a loss as to why there is even any secrecy about temperature corrections if this is all being done in a heavily peer-reviewed environment.