Doesn't add a lot of penalties. Maybe 1-2 per game (could also be a placebo affect). It does possibly add a few more blocking mistakes. You could go either way with this one. If you haven't done it, I wouldn't go back.
Not at all. You will still see INTs on bad passes, but every once in awhile you'll see that obvious INT get dropped (as Dallas CB did against SEA last week).
I believe it is DaReal Milticket who put this out. It definitely makes for better tackling animations.
I really like this. Your reasoning is spot on.
With these and maybe THROWS TIGHT SPIRAL OFF for non-elite QBs, I believe M18 will play about as good as it can. If anyone wants to add another layer to get some HB and/or DL rotation, then maybe edit STA (I still see some rotation without doing so). Now if we can only figure out how to improve the CPU play calling, especially on defense.
I know you've done the hard work by taking this on yourself. What platform and will you be making available for others to try?