It seems clear the two biggest impact positions needed in Oakland (and there are needs at most positions) are at Quarterback (if Flynn, Pryor or Wilson don't make a case) or Pass Rusher.
A lot of experts don't see the collective in Oakland as being that talented, and most predict the Raiders will be picking in the Top 5 of the 2014 NFL Draft, a lot of them say that the Raiders will pick 1st. It's an easy assumption to make, but with the schedule at hand and with some nice off-season acquisitions, the depth is a lot better overall, so it could be more of a Top 12 to Top 15 pick if things go well for Dennis Allen and Co.
However, that's a big jump for a second year coach, but it could very well happen if the offense moves the ball into the end zone with more frequency than in 2012. Hopefully, D.J. Hayden will recover and help solidify a reformed secondary. Praying for a quick and thorough recovery...as is Reggie McKenzie no doubt.