I wouldn't trust ancient dev chat material as gold, essentially the reality is from what I've found is that Outside runs are more aggressive and have a chance to go for more yards than inside runs, but they also have a higher chance to getting stuffed even when the team is in a prevent defense. The reward though is that when your player "breaks it to the outside" (which is simple dice roll) you will gain around 5-8 yds on average (excluding the big play broken tackles). Those stats are not 100% accurate but close enough. Running the ball inside will yield less -1,-2,0,1 yd rushes, but your good runs that aren't break through aren't as good as running outside.

Of course all of this depends on what your opponent is doing in terms of alignment and how many players are on the line, and formation disadvantages like 3 DL against a Wishbone/NDB package.

I think the argument at least at the D2 level that positioning your better players DL or OL to certain spots (DL1,DL2) or (OL3,OL4) is all an optical illusion, this game calculates outcomes based on averages, not individual matchups. In theory the average could come from the 3 inside lineman vs 2 outside but I haven't seen anything that has shown this to be true.

I've had some decent teams running almost every play out of the I-Formation. I experimented for a while with both inside and outside runs, but in the end I found outside runs got me more yards so I used exclusively outside runs to the halfback. Make sure your two best OL are at the tackle positions. I just assumed that the full back and TE would be blocking on run plays, but maybe setting them to block would be helpful as well. Always recruit blocking TE's, but I never found much of an advantage to having a good FB. And I used 95% as my stamina mark.