Always have been a fan of the 3-4. Key will finally be playing the position he was meant to play. I expect White to pass Riley on the depth chart pretty early on. The only questionable part to this defense is how well Key and Divinity will drop back into coverage.
I agree that the D will be improved over last year. I think late in the season, a lack of size leftover from the Chavis days will still be a problem in stopping the run. Tommy had all last year and off season to put some weight on these guys, and it appears to have happened to a large degree, but we are still smaller than I would prefer for our conference's style of play. You can see a number of positions where the Freshman who is sitting 2nd or 3rd on the depth chart is significantly heavier than the starter. Next year, this should not be an issue anymore, but I do think it will still hurt us some this season.
This special 3-4 of Aranda's has a lot of reads and assignments. Don't expect it to gel right away. There will be many coverage breakdowns early and on into the season. Might as well expect and prepare for it.
Exactly this shouldn't be the dumbed down Chavis thing. Expect guys to be out of position, missing assignments and so on
