At this point in the draft, it's wise to take the best player available:
Round 4: Dan "Boom" Herron, RB Ohio State
Herron is more of a downhill runner than Miller, and the two could provide a great 1-2 punch. Bernard Scott doesn't seem to be capable of handling a heavy load of carries, and I think it's best to start all over in the backfield.
Round 5: Juron Criner, WR Arizona
With no one knowing what will happen to Jerome Simpson with the law, and with Jordan Shipley recovering from injury, it would be a good idea for the Bengals to take a flier on Criner. At 6'4", 215 lbs., why not try to draft a physically gifted receiver and add weapons for "The Red Rifle?"
Round 5: Mitchell Schwartz, OT California
Schwartz was second team All-Pac-10 in 2010 and shows durability that you want from a tackle. Whitworth and Smith seem to have the tackle positions locked down, but it would never hurt to draft a backup who is NFL-ready and is always capable to step in when you need him.
Round 6: Chad Diehl, FB Clemson
6'2", 260 lbs., with a 40-yard dash of 4.72 seconds. That's a big, athletic fullback who can catch out of the backfield and lead through the hole. Chris Pressley is a serviceable fullback, but Cincinnati hasn't has a rock solid fullback since the days of Jeremi Johnson. A good lead blocker would go a long way towards Lamar Miller's success.
Round 6: D'Anton Lynn, CB Penn State
Lynn is a physical CB, standing at 6'0", 210 lbs. A highly touted prospect heading into college, Lynn could be had at a low price due to injury concerns. His stock may have slipped this year due to a neck injury, but he's back in action now and would provide great value with for a sixth-rounder.
Round 7: Derek Moye, WR Penn State
We saw it last year. Mike Brown took Ryan Whalen after already taking a receiver earlier. Derek Moye is huge. Some outlets have him at 6'5", but I've seen him listed at 6'6" as well. He has great leaping ability, but not great speed. He's a guy that goes up and gets jump balls though, and personally I think he's a steal if still available at this point.