The biggest draft needs for the Broncos are at cornerback and linebacker. Some of it depends on value, but the Broncos really don't have that many needs, so they have the flexibility to target the right players unless someone really falls and they can't resist.
With Champ Bailey out of the picture, they have to draft for the future. You typically don't want to draft a corner and throw him right out on the field because there is such a high learning curve, so this could be a good year to take one.
As long as they lock up Dominique Rodgers-Cromartie to a long contract and get Chris Harris back from injury, they can get a third corner who will get experience playing in the nickle spot and who they can groom for the future.
I've already made my case for Bradley Roby, and I stand by it. He's big, fast and physical. He's a hard hitter and he's not afraid to play the run—much like Champ—and he also has great ball skills. Best of all, he should be available for the Broncos to get, even picking so late in the first round.
If they don't go after Roby, they may end up targeting Marcus Roberson, who is projected to go just ahead of Roby, out of Florida. He has a ton of heart, he's a terrific athlete, and he's great at making plays on the ball. He just lacks the mean streak that Roby has, making him a little less physical. He's also not as good against the run, which is why he's not projected to go higher.
A round or two later, they could target someone like Victor Hampton, out of South Carolina. He's also a hard-hitting, athletic player, but that could be a problem in some situations. He tends to assume that his athleticism will be enough in most cases, and while it often was in college, it won't be in the NFL. He needs more development. If Roby and Roberson are gone, though, he could be a good project as a later pick.
As for linebacker, the Broncos need to either get someone like Shayne Skov to play inside, allowing Wesley Woodyard to move back outside, or they need to get a premier outside linebacker and let Woodyard run the defense from the inside.
Either one will work, but they do need an upgrade. Von Miller is a great pass-rusher, but they need someone to stay home and stuff the run. This would free Miller up to do what he does best.
An excellent choice at outside linebacker would be Ryan Shazier, also out of Ohio State. He's the ultimate competitor, and he makes a ton of tackles; he ranked sixth in the country with 143. He'd be a great complement to the pass rush because they could count on him to clean up anything that got past the line of scrimmage.
Predictions: Roby with the first pick, Skov with the second.