I have both Jones in my most important league- I am very nervous about both, and do not pretend to think they will be great because they are mine. That being said, my main hang-up is not on talent. It is clear to me they have the talent to be top 5 backs (with a little help from teamates, don't go crazy on me.....).
My concerns for both are line blocking and health. Some of this goes hand-in-hand.
Julius messed his ankle on a play where the defender was unblocked. This lack of blocking was a clear theme that even Parcells admitted. Kevin's problems, I can't explain as well because I only saw the horrible Thanksgiving game, where he had a nice 1st quarter, and then got hurt/benched/whatever that was.
It is around this point (2nd-3rd year) in some players careers that I have lost future stars by giving up on them. It is also the point where players either "get it" or they don't. Do they learn to block and catch? (Kevin needs this) Do they learn to toughen up? (Both need this) Sometimes we don't know until a certain tipping point in their careers.
My strategy (coming clear as I write this) is to listen closely to how coaches speak of them in the pre-season, and likely take the gamble that they shine. It would not hurt for the interior "push" of both lines to improve (read- Bentley FA at center).Trade value for both is not what I think they could produce. In fact, I ask myself if I would "buy low" on them. My answer to myself is that, yes, I would.