It is pretty amazing how many people who saw Peter Jackson and Jack Dempsey fight (or for that matter you can add Johnson Jeffries and all in between) who consider Jackson to be the greatest fighter of all time. And if you rate Jackson as better than Jeffries, Johnson and Dempsey, then, well you could end up with a very, very high ranking. Certainly it seems more than reasonable and perhaps even expected that he should be a class above Langford, McVey, Jeanette, and Wills, as a starting point. I am starting to think top 25 is pretty much a necessity. http://trove.nla.gov.au/ndp/del/article/17253016?searchTerm=larry foley series&searchLimits= Totally off topic, but i thought this was an interesting article, because it is the only account i have ever found (from what i can remember) about the Starlight rollins v Bob Fitzsimmons fight.
There are good reasons to believe a prime Jackson would beat a prime Corbett. And that a prime Corbett beats a prime Jeffries. I think it's very reasonable to rank Jackson above Jeffries and Corbett, and above Johnson. How he ranks against the great John L. Sullivan I don't know. Or how he ranks against later fighters like Dempsey, Tunney, Louis, Ali etc. I'm not sure.
i agree totally, also many thought a prime jeffries would have defeated a prime Johnson. an old friend of mine who is in his 70s told me a tale that his grandfather seen Jackson fight at Grasmere Sports Cumberland in the English Lake District he also seen Sam Langford fight there yet rated Jsckson as the greatest fighting man he ever set eyes on. i checked local libraries old Newspapers and found articles to verify that at different times Jackson 1889 Langford 1909 both apeared at Grasmere Sports. Langford had 3 fights 3 KOs, Jackson 2 fights winning both.