When her passive is down, it needs to be down.
This is a meaningless statement. The issue at hand isn't anything helping her get her passive back up, it's an issue of what makes it go down and why in particular minions need to bring it down.
Asking for her passive not to go down at a certain level is like saying "Oh just wait, once I get to level 11, I won't have to think as much when it comes to my engagements."
How so? This isn't about engagements. It's about minions. The most important factor this affects is her ability to roam and push, not anything involving engagements or teamfights. It gives me more options and a bit more leniency for that purpose. It's not going to help fights in any significant way.
I don't think Riot will condone mindless gameplay.
What do you think is mindless about it?
If you want anything to happen for Miss Fortune, it should probably not affect her passive.
Why not? The passive has unnecessary functional problems which could be fixed without majorly buffing her. As I see it. changes that make something less frustrating to play but don't really impact enemy interactions or power level are good changes.