If we're ranking them by importance,
1. Right Tackle
2. Wide Out
3. Defensive End
4. Cornerback
Of course this is assuming McCown or King can start effectively and that is not a given.
Filling the RT hole is a must, especially with young quarterbacks. Boldin will become the master of the double move if the Cards can get the QB time to throw.
I think it would help to get a receiver who would open up the field more. White was my recommendation, but a few are still being dangled out there. The current unit should be better if the line is improved. Johnson should stay on track and become about a 700 yard guy. Poole will be a Ricky Proehl-type receiver, given the opportunity and he understands the red zone. Boldin will draw constant double-teams, but still be effective if the QB has time to throw.
One pass rusher isn't enough. If KVB is healthy (which is a big if), he might start with Johnson rotating with him on passing downs. I'm not certain Pace ever develops. He has so far to go. Berry helps, but he is not a one-man gang and he may get frustrated, like Rice did, if he draws constant double-teams. Also, what happens if Berry gets injured? There is no pass rushing depth.
If Hill comes back and Starks is healthy, the Cards are fine at the corner. I'd still like a better veteran than McDaniel on my roster.
As to the other previous positions mentioned, I think there are enough candidates the Cards will be fine at guard, but there's no one to replace Clement at tackle.
The addition of Berry, playing in front of small linebackers, does raise a concern and the likelihood of more lost time due to injury. Still, the team has its best depth at this position and I could live with what they have at this stage of team re-building.
A premier running back is a luxury that can be addressed down the road. I can't imagine it will be addressed with Clarett. He has bust written all over him. He also looks injury-prone, which won't be helped by entering the draft before his body fully matures.
Finally, I didn't mention tight-end. I think Green's comments have been directed at what I saw. Jones doesn't play mean. He needs to pound his blocks and be more physical. Too often he tries to finesse people. I wouldn't change this season unless somehow they traded down and Winslow was the best on the board. That would be about the 9 or 10 slot.
Finally, it may be too costly to fix all this in one season. Still, with some cap room remaining and two impact draft picks (3 & 33), the Cards could get very close.