The weekly release for the Ohio State game last year shows that Michigan ran a 3-4 defense (page 21). Roh’s position was specifically labeled OLB (same as this year) and Brown was playing SAM. Thing is, Brown was a LB in responsibility only; he still had the characteristics of a safety. So, if you count him as a “box” safety and not a LB, you end up with a 3-3-5 anyway.
The only difference I can really think of is the difference between a 3-4 alignment versus a 30 stack alignment. Actually, starting off with 8 guys in the box every time with two of those guys being fast enough to cover people if necessary seems like a good thing.
For whatever reason, I had it in my head that Roh was a DE so I thought we were going from having 4 down linemen to 3. Now it just seems like a change in nomenclature more than anything else. Am I missing something?