Admin Notes
As noted, the combinations can be endless. We had such a system in the past, and it was really painful to get every defensive option set up (probably the reason defensive coordinator is a full-time job).
Do folks have suggestions on ways this can be simplified to just 1-2 knobs, so as to not add too much complexity?
7/27 - still waiting for additional suggestions / comments

Comments
Robert Redmond: Aren't 1 Gap defenses associated with 4-3 and 2 Gap with 3-4? If we were looking to add bonuses and takeaways perhaps it's better added to the formation used rather than an extra option. If it was decided to added maybe a 4-3 defense could give a + to defender's speed and a - to weight while a 3-4 defense could gain + to weight and a - to speed?
Coach Scarn (May 27 14:31:08 2020 ): You’re right Robert, in the traditional sense of base defense (Go Hawkeyes!) There are so many hybrid defenses, like 4-3s with a NT that plays 2-gap while the other three play 1-gap, or 43s with a NT and SDE that both take two gaps to the strong side while the other two shoot their gaps. Even 34s will slant one way or the other, usually to coincide with blitzes. DEL football does a great job of simulating straight up defense. I’m looking for ways to expand from 2-man/2-zone. I thought of two ideas to implement this. 1. A check box on the individual play screen to shoot the gaps for that play. Increases chance of loss and run to second level. 2. An option on the play screen to designate the gap control. “Pinch”: DL slant inside to take away interior runs. OLBs have more responsibility for sweep. “Strong/Weak Slant”: DL slant strong or weak. “Fan”: DL slant outside to take away sweeps. ILBs left more alone on middle runs. “Standard”: What we have now. If we could figure out the right balance, it wouldn’t be a big exploit. Rather, defenses could scheme to shore up weak spots. Teams with good OLBs for example, might be more willing to stuff the middle and hope their outside defenders can handle it.
Gregor Ellis (Jan 10 11:20:43 2024 ): If the formation viewer is correct, 4-3 and 3-4 Tight alignments are always 2 gap and Loose alignments seem to be a hybrid affair. I would just like to have a Line option that is 1-gap (Nose always to the weak side of center wi odd # of DL/DT's in weakside A gap and strongside B gap with even # of DL, and DEs on outside shoulders of OTs) 2-gap (current approach all DL if Tight and DEs on OT/TE outside shoulders if Loose)