I have been fooling around a little with the engine of late. It seems from my perspective, that FCP was fixed (honestly fixed) by making it more susceptible to fatigue, more requiring stamina. Now that we have team averages, it appears 80 team average stamina is great, and 76-78 is pretty good.
I don't think you can win a national title FCP without a starting ten near 80 in stamina, as well as all the other core skills required to win it all. I also think FCP used to have the least trouble vs an equal or superior team (i.e. in the NT), now I think it has the most trouble with such a team. Not impossible for a FCP team to win it all, just harder than it used to be.
If I had to rate the odds of which defense you run, and it's impact on winning it all, I would rate m2m 1.1, fcp 1.0, and zone .9. But, I do think zone has its place, there are reasons and ways to run zone to maximize some teams, but not the traditional ryan75 west conn or dr gill or lostmyth dynasty type teams, man is the way to win with those now, just as fcp used to be.
I also am of the opinion, when seble realized what he did with ratings, he upped the impact of IQ again, for those around long enough, again, IMO, returned it more to where it was at 6 or 8 years, not HD seasons, ago.
All opinion, like many things in this game, no one knows for fact what is going on except the game designers, and they have kept us all guessing, some of us for near 8 years now, I don't think there is any reason to think things will change, so guess away!