I think that you and Thoughsleader both have some good reasoning when it comes to comparing Katir and Nordås. And I even think I would give you the upper hand here; detailed and good reasoning…
But this also shows how complicated analysing progression is, because I’m quite certain both you and Thoughtsleader may be very wrong… (About both Katir and Nordås)…
F.ex Katir’s two years of running 3.36 before the breakthrough of 3.28 -your analysis seems right (first look) because he doesn’t (unlike Nordås) win the races. But you and I don’t know what that means -we can only speculate, and speculation is a thin animal! Even if Katir doesn’t win the races he might have something unraveled / unreleased in the 1500m (indicated by being on a plateau for two years). Or you could be right -no way of knowing; the Devil’s in the details, and we will never have them (detailed enough). And even Katir’s very suspicious whereabouts don’t need to mean drugs -I could come up with a handful other explanations (that of course might be wrong)…
It’s extremely dangerous to use a linear logic when it comes to the human sphere -very smart people do it all the time, with very flawed answers! Just have a closer look at this thread -nobody has something that even look like proof for their claims. -Their lists of suspicious athletes could easily be transformed to no suspicion at all, if using a different set of indications.. F.ex Jakob suspicious only based on performance / dominance -how will the same guys explain Herbert Elliott. Was he also obviously doped..?
Lastly: I could erase everything I have written above, an nevertheless easily rip apart your reasoning (even if your reasoning might be right -unfounded guesses can always be right sometimes): I could rip it apart simply by narrowing the whole thing down to only be a comparison between Katir and Nordås, although now analysing the 5000m. -Nordås has been crappy at the distance for many years (despite prioritising it). So what if he now eventually runs sub 12.50 (which I expect) -must he then be doped? (Following your logic from Katir’s progression in the 1500m!?).