I'm afraid that I'm no expert. However I don't see that it has any relevance to evolution versus creationism. Only YECs have any motive to even try to attack cosmology but the alternatives also acknowledge a vastly old universe so there is really nothing of any real use to them.
Looking at the letter itself the important word is "quantitative" - it isn't that there aren't fulfilled predictions it is that the numbers don't come out close enough. It may well be correct in that.
It seems to me that the letter is primarily the work of the supporters of slternative theories who want more funding for their work but sadly can only get it by knocking their main rival rather than putting forward to a superior alternative.
I did recognise a couple of the names - from past discussions I get the impression that Aarp is headed for irrelevance by clinging to his pet ideas despite the evidence (as Feduccia is over bird evolution but more so). So it is no surprise to see him on the list. Von Flandern has gone even further and may qualify as a full-fledged crank by now Lerner is the ony name that gave me any pause at all.
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