Jefferson is a guy on the rise. If OJB resigns he probably won't be ready to start the season and Woods still will be a question mark though he should be good to go. Last year showed us we need at least 4 WR as people get hurt.
Agree on Jones and expect him to continue to grow and improve. It seems likely that he will be a star.
OL and CB seem most uncertain right now though depth issues could potentially be an issue at almost any position.
It is hard to get a good read on the players they are developing because you never really know how good or bad they are until they step out on the field. Howard, Blanton and even Higbee looked really good once they got a chance to get on the field.
Also last years draft with the Brown's, Tutu and Harris right is still a big question. I don't think they expected any of those guys to play a significant role outside of special teams last year and it will be interesting to see how they have developed.