Around Dix personally, I don't think there's a cloud. He is in the 100m list at 9.88, very near the top.
It is that 200m time that for me is suspect, when Blake ran a WR-quality 19.26 after having missed his start.
Although he has smoked a 9.69 100m, that 19.26 still stretches credibility, especially when the 200m = 2x100m (19.38) time theory is considered, and especially when it is considered that he missed his start, which would take his 19.26 to something like 19.16, and between that and 19.38 there is a 0.22 discrepancy, which is huge.
Dix's 19.53 seems to me to suffer from a similar problem. His two next-best, remarkably consistent and all with essentially the same wind, were 19.69 and 19.70, about .17 off, which is huge.
If NOT Spearmon, then Dix, for sure, but then Dix would be WAY out in front of the others--Spearmon, Fredericks, Marsh (19.65, 19.68, 19.73 headwind). If the 19.53 is discounted, Dix is right in there with those 3 guys, at 19.69
Which would make the top 3 times 19.65, 19.68, and 19.69, which to me is more believable than Dix having gone 19.53, considering Blake's alleged 19.26 time.