A few points and counterpoints to what Jon said ....
While the "simplicity" of Iowa's scheme allows for guys to come in and play fast. That still is NOT to say that there aren't a few particularly critical cogs in Iowa's scheme. In particular, the MIKE spot is particularly crucial to the Iowa D (as it is for many/most Ds) because the dude makes sure that the front 7 are lined up right. Similarly, the departure of Iowa's veteran safeties will likely hurt because Iowa's secondary gets the coverage calls made by a safety.
What are the consequences of the above observation? First off ... it may prove to be one of the BIG reasons why Morris remains at the MIKE LB spot. Anybody who watched Iowa's film closely, Pat Angerer did a MUCH better job getting our DL aligned in his 2nd year starting than in his 1st year starting. I think that many folks have wrongly maligned Iowa's 2010 DL for reasons that they don't understand. The fact that we were stuck with a TR FR making the calls, in addition to the overall drop in LB coverage skills ... the 2010 Iowa DL didn't enjoy the same benefits that they had the prior season.
What is the implication of all this? I really believe that having Morris back at MIKE with a year of experience under his belt will reap benefits. I think that we could actually end up observing IMPROVED DL production as a result of this. Also, provided that Nielsen returns and is healthy ... Iowa's LB corps will enjoy a HUGE boost. Just as Jon mentioned, Nielsen was doing a GREAT job of filling Edds's shoes. Given the athleticism and coverage skills of Morris and Nielsen ... having both of those guys healthy and with the added experience makes our LB corps that much more dangerous in coverage. Again, that can really help out our DL.
But then there's the negative of losing all that experience at safety. In that regard, we'll be missing effectively having 2 coaches in the secondary. Furthermore, we'll likely see more botched calls in the secondary ... which could end up exposing us more than we'd like to some big plays. We were similarly exposed some in 2005 and that was even with Paschal having experience. Then, in 2007, our safety duo of Dalton and Greenwood got surpremely "exposed." Of course, it didn't help that Dalton was pretty bad at reacting as he was getting out of his backpedal.
What can we expect from our new starting safeties? To be frank, I really don't know. From what I've heard, Greenwood and Sash took Tanner Miller under their wing. It sounds like they really tried to engrain the need for film study to him ... and given the fact that he saw so much quality game time as a TR FR ... it would suggest that the kid might be a bit of a "natural."
So what does that mean? Are we going to be having a TR SO making the calls for our secondary in 2011? I don't know ... probably. As for the SS spot, I have no clue. I really think that we could end up hearing about a three-way battle there between Donatell, Bernstine, and Hitchens. And, mind you, I wouldn't be shocked if Law were given the chance to enter the fray and at least contribute on special teams. However, we'll still have to see how everything plays out.
As a parting shot, I like to point out the following observations about the 2008 Iowa D. By most accounts, the '08 Iowa D was much better than nearly anybody expected. The group was statistically pretty impressive ... although the group did have some issues getting TFLs (or, at least, getting sacks). Anyhow, the '08 Iowa D featured ....
.... 2 first-year starters on the DL (Clayborn and Ballard, both SOs at the time, and both at DE)
.... 2 first-year starters at LB (Angerer, a JR, at MIKE LB and Hunter, a SO, at WILL LB ... and Hunter nabbed the spot due to Tarp being out with an injury)
.... 1 first-year starter at S (Sash replaced Dalton ... largely because Dalton was just bad. It's worth noting that Greenwood was also just in his 2nd year starting and was a SO)
.... 2 first-year starters at CB (Fletcher was a veteran SR who had seen prior starts, however, it was officially his first year as a full-time starter. Spievey, a SO at the time, was in his first year starting at Iowa at CB.)
Yeah, read it and weep ... SEVEN first-year starters on the '08 installment of the Iowa D.
All of a sudden, things don't necessarily look quite so bad for the 2011 installment of the Iowa D. The '11 Iowa D will feature ...
... 2 first-year starters on the DL (1 at DE and 1 at DT)
... 1 first-year starter at LB (the WILL LB spot ... and that assumes Nielsen will be "good to go")
... 2 first-year starters at S
That's it .... replacing 5 starters.
However, one of the most important questions is this ...
Where will the leadership come from for the 2011 Iowa D?
Part of what made the '08 Iowa D so good is that King and Kroul were great leaders. King was a freakin' Norse Barbarian enforcer ... who's gonna screw with him ... especially given that he was a 4-year starter?