The 3-4 defense appears to be on the way for the Irish. This is great, imho, for the Irish. I coach HS FB and have read a bunch of stuff and tried different things using a 3-4...here's my 2-cents...given the economy, it may not be worth that much...
Def. Backs--Base Cover 2 system means little change in overall scheme for the youngest and most talented unit on the defense. There will be "tweaks" (COVER THE DEEP BALL and BOTH SAFETIES NEED TO BE INVOLVED IN COVERAGE come to mind), but the base system won't be foreign to them. Switching to a 3-5-3, 4-2-5, or a Bear 46 would mean significant new learning. Plays to the strengths of the existing system and roster (new recruits included).
Linebackers--Look at the available players:
Crum (6-0/220)ILB/OLB, S. Smith (6-3/242)ILB, Washington (6-1/239)ILB, Quinn (6-2/215)OLB, T. Smith (6-0/230)ILB, Brockington (6-1/220)ILB, Richardson (6-2/228)OLB/DE, Vernaglia (6-3/230)ILB/OLB, Travis Thomas? (6-0/215)OLB
There are 2 LB philosophies I've seen with the 3-4:
1. Big inside--can go smaller/quicker at DE because ILB's can take on O-line blocks
2. Big outside--can contain the outside with LB's to free up D-line to stop the inside runs--OLB/DE tweeners could benefit from this version.
Looking at the available players and what they've played so far, this is a good quality group that gives the coaching staff flexibility in how they want to use the 3-4 defense. If the D-line develops, this group platooned or used in specific situations. Some smaller DE's could add to the size of the the OLB group as well.
Defensive line--This group has some players that could really benefit from this system, imho.
Smallish DT's (250-270) make very good DE's in a 3-4--quicker than typical DT, but able to take on the OT's/TE's/FB's.
The traditional 4-3 DT's need to be 270-300+. This is easily the most difficult position to recruit, especially for ND. Too many of them get nabbed for the O-line in HS. In a 3-4, the need for those players is cut in half. Only the nose needs that kind of bulk. Including Williams (recruit), ND has 3 players that could work the nose--maybe 3 with Kuntz.
The zone blitz possibilities can be better in the 3-4, because there are more LB's than they are in the 4-3. Stunts tend to go better in an odd front, too because there's more room to operate than in the 4-3.
I like the way the depth chart and the 3-4 fit...it could be a very pleasant surprise on the defensive side of the ball for the Irish.
Lord knows, they're due!