First I should say that I love the thread...thank you.
but since you've put me on the defensive...
I interpreted the question the same way the voters for the pro-football Hall of Fame did...how can you discard the greatest and most dominant back of all time simply because his prime years did not overlap with the NFL for very long?
Grange was a charter member of the Hall of Fame, the prestigious class of '63 -- with Thorpe and Halas. One wonders what those idiots must've been thinking since he only had a "mediocre" career.
He had 3 great years in pro ball, one in the NFL and 2 in the AFL. As you're aware, the Patriots were an AFL team -- anyone who wants to enshrine Gino better hope there's no bias againt the AFL. I suppose O.J. Simpson, another AFL back, must also be ignored??
Grange's AFL team, the Yankees, eventually became an AAFC team...the AAFC was the league where Paul Brown and Otto Graham had most of their success.
I answered the question literally -- "most dominant back in NFL history" -- absolutely no concessions for career length.
Neither Gale Sayers nor Earl Campbell played more than 2-3 injury free seasons...should we therefore ignore them too?
Up until the 1940s (and really the 50's), all the best coaches and teams were in the college ranks. For example, Grange's coach at Illinois, Zuppke, was a far more significant innovator than Halas (who is commonly and wrongly credited for the invention of the T formation).
Luckily for the pro game, the best of the college game and the NFL would occasionally overlap. Thorpe, Nevers and Grange all had pro careers which were FAR less significant than their college careers -- but they were inarguably the 3 most dominant backs from the 1910-1935...unless this is strictly a cookie-cutter "pure NFL and NFL only" thread (which strikes me as rather silly), then I don't see the point of leaving them out of any discussion of the "most dominant backs."
Now, if we're looking at "all-around" backs, then durability is a major criteria...but I interpreted the question narrowly on the question of "dominance" and broadly on the question of "NFL."
Let's not pretend Red Grange didn't exist simply because the NFL was a joke prior to WWII (and if not for Graham and Namath the League would almost certainly have a different name today).
again, thanks for the thread...always fun to inject some history into the offseason.