Bellamy would turn him into a complete footballer, just like he did with Papy...
I'm not sure that is correct.
Papps has some natural attributes which are not evident in Dufty namely physicality and the burning personal desire to "do whatever it takes" to accomplish the best outcome possible.
I believe these are traits you either have or you don't and can't be coached however if you have them I do believe good coaches can "heighten / accentuate" them thus making a player better.
Dufty is 25 and not shown the desire to put his body on the line each and every time nor has he shown the burning desire to be that player who is going to be "there" when it most matters which is something Papps has in spades and his enthusiasm to be involved in all facets of the game is simply outstanding as was the case with Slater.
There is also another glaring difference between Papps and Dufty and without trying to sound horrible it is evident if you watch either being interviewed.
Some players like Papps are extremely mature, focussed, team responsibility aware and highly professional / business like and always capable of seeing the bigger picture and then there are players like Dufty who are not capable of seeing the bigger picture and tend to focus on individual aspects with the odd glib comment about "we have to do better".
No doubt Dufty has the desire to be faster and to score more tries but that would not be enough for Bellamy and unless Dufty was willing to do all the other stuff and self sacrifice I doubt Bellamy would bother with him as the Storm culture does not allow for players who have less than 100% commitment to all aspects of the game.
No doubt some other clubs and coaches would most likely accept Dufty as is and if he ddn't improve they would still be be happy with the highlight real but IMO not Bellamy.