Now that the Niners have signed Bolden, I think we can lock in the starting WR depth chart with Crabtree and Boldin. Barring injury or a dramatic fall off of productivity, I do not think many rookies will break into that mold. Also, assuming that Jenkins steps up this year (crosses fingers) he should hopefully improve his production. Combining all of that with the potential return of Manningham and Williams and the importance of the TE position, the Niners don't really have to reach for a WR IMHO.
However, looking down the road, Crabtree's next contract expectations will be HUGE. Boldin has a limited number of years left, and there is no way of knowing how productive Manningham and Williams will be.
Finallly, WR take time to develop. There is a common conception that it can take up to three seasons to really determine how good they really are.
I believe that the Niners should draft a development WR, probably in the 4th or 5th round. I'd like to see someone who is purely a WR on the outside with some decent speed and a redzone target. If Darick Rogers falls to the late 3rd, he would be a good option, or if they package late picks and move up, that'd be great too.
Who are the best mid round prospects at WR who could challenge for a starting spot in the next few years?