Do not let me deter you from finding out more about m15 sliders and making contributions to OS. The more information the better, regardless of whether it's right or not, it at least creates a better understanding of the madness that is Madden Sliders. EA got it right by pulling sports gamers in, especially those that are obsessed with making the game as close to NFL resemblance as possible. If I were them I would create sliders too for others to edit if I knew most players were going to take more than the time for the return policy for the game to edit them, "probably a broken sentence"
I'm not saying I'm right, my mission is getting it right. If more ideas are thrown out there and more concepts to test, we will get closer to figuring out this mess. If people just give up and don't contribute, we will get nowhere, that's the last thing I want to see.
I, you and others are putting a lot of work and effort into giving the community a better game because we care about making things right. I personally have spent countless hours in just the past few months testing, testing and doing more testing of different slider combinations, difficulties, trying to bring out the best animations while keeping stats as realistic as possible. That time I have spent as well as the time you've spent among others should not go to waste. Yes, it is not our job to make EAs game better but hey, we can and when we do that'll be a huge milestone because it feels awesome to see that your time and effort amounted to something. It would be a pity to "work" anywhere from 40-300 hours or more then let it all go. Then again I'm the optimistic type, you can turn anything into a positive.
As far as your concepts, who says slider makers don't understand them?
To answer your question(s). Pass Rush is important because of the amount of time the QB can hold on to the ball before throwing it. This will in turn affect YPA, targets and comp%, that is why I suggested to change it along with the DPI/OPI.
90/10 is not the magical number but what I do know, at least for All-Pro, these sliders offset each other. A higher DPI = more aggressive secondary, a higher OPI = a less aggressive WR.
I have not seen the code in Madden so I cannot answer how DPI/OPI relates to WRC, QBA, PBL, etc, all I can do is say that I have tested and repeated (as scientific studies would dictate) to ensure my results and this is the conclusion I came up with. Is it definitive? No. It does however hold water because it can be verified.