I think so much of this perceived set of "tweaks" is entirely down to "team spirit", especially if you're starting again on a whole new difficulty level with a new team.
I've ran some tests in my ML career, replaying the same game 3 times on each difficulty level (Pro to Superstar), 10 minute halves, quitting back to the XMB between matches just to keep it clean, and there's no difference for me. With an 80 team spirit, as Hull against Bournemouth, I'm smashing them an average of 4-1 on Professional, 4-1 on Top Player (which I thought was amusing - same average score on two different difficulty levels), and they're beating me an average of 2-0 on Superstar.
With a different team spirit, it's an entirely different set of results (but again, Pro and Top Player are very similar for me).
I played a Europa League game against Sevilla on Superstar and the stats at the end of the game were bang on, super realistic, and I'm happy to have lost (I win on any other difficulty level with a team spirit of 80) - but I hate the way they ping-pong the ball around without looking, it's the one major bugbear I've got with the game.
If I lower the difficulty, I'm beating teams I shouldn't be, but one of their goals came from a streak of ~8 first-time passes and ended with a first-time shot, it didn't look good and it felt like a massive cheat.