I like the concept of being a passing team and switch to run if pass isn't working (i.e. defense is playing Pass defense), and vice versa.
I would like to see consideration of additional changes as follows:
1. set defense coverage in Man-to-man (either aggressive press coverage, or conservative off line of scrimmae; CBs are key defenders), or zone coverage (CBs, S, LBs all factor in coverage)
2. set defense blitz level/type (basic blitz = 1 blitzer, multiple blitz = 2 blitzers, max blitz = 3 blitzers, also have a zone blitz)
2a. set offensive blitz protection to either basic (no extra protection), moderate (TE/RB chip blocks, they go out for pass if not a heavy blitz), or max protection (TE/RB stay in to block and don't go out for pass)
3. set defense line style to 1-gap (Defense needs better DL than LBs... DTs try to make plays, LBs have to fend of blocks) or 2-gap (Defense needs better LBs than DL... DTs occupy OL and don't make plays but LBs have free run and make the plays), you can recruit DL/LB to fit your style
4. set O-line blocking to Zone blocking (OL requires BLK, GI, and Tech) or Man-to-man blocking (OL require BLK and Str), you can recruit OL to fit your style
5. Offense can call individual plays, by setting a percentage of times they can each be used. Maybe have an inventory of 10 to 15 basic offensive plays. (For example, if there were 10 plays, a SIM team might set all of them to 10% each and run them equally). Called pass plays would determine the primary receiver, if he is covered and QB decides not to throw, it's as if current system is in place and QB makes another pass or scramble. Play-by-play results would need to identify play that was called (ex: "QB incomplete pass to WR on skinny post", "RB rushes for 4 yards on draw"), so defense could scout as if watching the plays on film.
Example of play inventory would be:
RB screen (more effective if defense is rushing the passer),
Bubble screen to WR (more effective when the defense playing off line of scrimmage or CB is poor tackler),
Crossing pattern (more effective when DB/LB doesn't have GI to pick up in zone or DB doesn't have Speed to follow WR in man-to-man),
Deep vertical "go" routes (more effective when WR has speed and/or DB doesn't),
Stop-and-go, Sluggos/slant-and-go, Out-and-up (WR needs Tech and Speed),
Out/sideline patterns,can be deep or short (WR needs Tech to get feet in bounds, these also stop clock in hurry-up mode),
Post/skinny post patterns (up to Safety to make play on WR),
Curl routes/come-back/slant routes for possession receivers with little Speed/Elus but good hands,
Draw to RB (more effective if defense is rushing the passer),
Zone read runs (either QB/RB carries, depending if Aggr run defense and DE charges then QB keeps, if Consv defense and thus DE slow plays then the QB hands off to RB),
Basic RB inside runs (DTs and MLB defend) and outside runs (DE and OLB defend).
QB draw (effective with running QB and/or blitzing defense)
QB roll-outs (pass or run depending on GI and play available)