Yes a ploot system would statistically leave you with less loot. Anyone interested in minmax gameplay would not be using this option, I would guess. But not everyone min/maxes at all times. Some might even prefer the ploot play style. This would simply be an option for them.
And I wouldn’t quite call this someone managing luck. It’s just another layer of RNG. But again, what you are doing is simply illustrating why you would not personally want to use ploot. This is in fact not an argument against it since the solution for that is you simply not joining ploot games.
Of course you may be inclined to say that this would split the population. When in fact it would increase the amount of public games because the only viable way to currently magic find is to do solo games. This would bring people out of there solo private games and into public games, this more games, and less division in the player base.
Currently the only real reason to group up is for Baal/tomb runs and rushing/questing. Adding a personal loot option would not change these games whatsoever. They would still be just as necessary.
I’d love to get into more detail with you as well. I’m on my phone now so can’t really construct a very detailed post but I appreciate yours and will get back to you further later, especially if you have more input.