And you realize there's no value in it, right ? Tkachuk wasn't the clear BPA at 3 on draft day, which is all that's relevant here and in the context of the upcoming 2019 draft. If we had their 2020 point totals, then we could use that "strickest" definition of BPA, but we don't. That's why in that context the very definition isn't even standard. If we're going by who's going to score more points: well there's no real way to predict this when players don't have much seperation between them. If we're going with what's been accomplished, then everyone will weigh performances in different leagues according to their own biases. If we go with translatable skills, then two different pair of eyes will value differently as well. Obviously, this doesn't apply when there's a very significant gap between players (ex: Kotkaniemi and Cam Hillis), but when we're looking at the players picked between 3 and 10 last year, that's a different matter.
If I had to give an example from a professional, I would refer to Gordie Clark, who had Kravtsov as the 2nd best forward and as an NHL ready body. Meaning, he likely had more than 3 NHL ready bodies last year. (I will also add, for form, that context matters: a rookie playing with Mark Stone on a team with multiple guys flirting 0.8ppg and over will likely produce more than another one on a team, in a lower scoring league, that 1. Doesn't score 2. doesn't get equal opportunity, despite producing the most offensive chances).
If I had to give an example closer to home, I would refer to you. You had Zadina as the clear no. 3 player. You had him scoring 20 goals this year. (wait... so this means you didn't have Svechnikov as an NHL ready draftee ? Only Dahlin, Tkachuk and Zadina ? Really ????). Putting yourself in your own shoes at the time of the draft, it wasn't so clear who was BPA now was it ? Now, imagine if you had scouted other players, notably Kravstov (and Kotkaniemi too actually). This might have been even less clear. This is why you get guys like Clark and Chainey who aren't willing to call Tkachuk the no.3 clear BPA.
