On the contrary, the only way to get better and learn to do those things is seeing yourself on film with quality game reps. So, it is either we play starters only, or we play 28 guys, get them on film and teach them how to effectively line up and communicate.
You need to play 4 edge players. You need to rotate 4 interior DL guys. That's 8. You need to rotate 4 LBs, that's 12. You need to have 6-8 players in the secondary based on coverages, packages, etc. That is at least 18. And that is minimum if you want to have a successful year long defense.
For the most part we have been doing that. Against Rice and Wyoming, we did go into the 3 deep on the DL and safety positions.
28 defensive players have recorded at least 2 tackles. That's not a bad thing IMO.