I can't speak for others, but for me gap assignments in Madden need to relate to what coverage and front is being played, both of which will dictate the technique played by linemen/linebackers.
On my phone so I won't go into huge detail, but basically I want to see front seven players wrong arm vs. gap schemes when playing a two high coverage, allowing the ball to bounce to force player (CB in Cover 2 and Safety in Cover 4).
Conversely, I want to see force players in a single high defense like Cover 3 always fight to keep their outside arm free, looking to turn any run back inside where the defense will have a +1 advantage in the form of an extra guy from the secondary.
Up front, I want to see linemen aligned directly over an OL (0 Tech, 2 Tech, and 4 Tech) two gap and attempt to stack and shed once the HB declares which side he will go. If a DL is not aligned that way, though, then obviously he is a penetration player who's job is to get upfield more.
Quick note on 1 Gap vs 2 Gap: the latter will be the direction more teams move in over the years to combat the spread run game. You see it in college with Stanford, and even Oregon became a 2 Gap 3-4 once Chip Kelly came on board as OC and started torching their 1 Gap 4-3 in practice with all of the read schemes his offense presents. So having said that, there needs to be a distinction in the game between a 3-4 where the DE lines up outside the tackle (1 Gap 3-4 Wade Phillips style) vs a 3-4 where the DE lines up head up (Eagles, Steelers, and 49ers immediately come to mind).
IMO, virtually every exploit that occurs in Madden is because sound defensive logic has not been programmed from the ground level: the guys making the game instead opt for quick fixes like this "Wide 9" crap as a run stopper for edge runs (lol). Each player should have a simple decision tree based on coverage and front vs. run and pass (i.e. against a kick out I do this, if #2 receiver runs to flat I do that, etc). Have awareness govern how often they execute vs **** up their assignments and call it a day.
Unfortunately, if any of this were going to occur it would have happened now that next gen is up and running. Instead they've decided to build on the legacy of already flawed code from the 360/PS3 era.