Unlike others, I never had major issues with the game engine.
What caused me to leave was a few things that I will check out over the coming weeks:
1) The contemptible 'Enthusiasm' rule.
2) The draft not bringing me good picks after I maxed out my spending. And, yes, I did win my league and get promoted to D III, so I picked last in each round.
3) A transfer market dominated by cash-rich coaches from new countries who had DIV I money but DIV VII brains.
I'm sure there were other annoyances, but that's the three that come to mind as I write.
Others may, and will, disagree with me, but all three still existing will mean I'll be out of here again after a season of testing.