I think most could write a book about how this is just a bad idea no matter what your intentions. It opens a can of worms that saps the trust, that "owners" need to have with each other, out of the league in question.
It takes almost no time to simulate multiple seasons with a good computer. You say it would take many seasons to be able to get the info to "really": cheat. So who sets the limit and what is it? Can I do 50 season replays, 75, 100? If not why not? I'm only simulating the sim (I honestly don't know what that means)
In a league that allowed this (and none ever will and survive) I not only have to worry about how to run my team and compete but I now have to worry about how many sims should I run to keep up with everybody else. Sounds like a lot of fun to me.
You say you want to do analysis on your team by simulating ahead. I can't see how one does this without cheating. Let's say I have a stacked lineup and on my team is a great hitter that plays CF poorly. I also have a weak hitting gold glove CF. I analyze this by simming 5 seasons with the hitter in CF and follow up with 5 sims with the gold glover in the lineup. Compare runs scored and allowed with each variation and then set my lineup accordingly.
I have the best basestealer in the league and others that are above average base stealers. I max out my strategy on stealing for him and the team to steal as often as possible. Sim season and get results, with runs scored being my primary interest. Now I set those same stealing strategies to as low as they can be set (even for the best stealer in the leauge) and run the sim. Check runs scored. I could run this setup 5- 10 times pretty quickly and determine which strategy would be more successful. I might find that even though being thrown out 40% of the time my team still scores more runs with a strategy of steal as much as you can. Or I might find that though my runners are only being thrown out 20% of the time that my runs per game actually go down. Guess which strategy I'm going to use? Correct, the one that results in more runs scored! Of course this isn't cheating I'm just analyzing my team
The scenarios are unlimited as to how one could "analyze" their team and cheat. But of course that's ok because everyone is allowed to do it
Or am I over reacting because there is a limit to what and how you can sim ahead? And again, once you allow simming ahead who sets those limits?
Isn't the simplest and easiest thing to do is what leagues do now? IE any simulating ahead is considered cheating and keep the field level for everyone? No exceptions, no excuses.
Look at baseball and corked bats as an example. I've heard, of course, people argue it helps the batter. I've heard it makes no difference. I've heard some argue it hurts the batter. I haven't heard there is definitive proof of any of these theories (someone can correct me if that's wrong). But for the sake of argument say none of the above can be proved shouldn't baseball allow corked bats? Or isn't it just simpler to have a no exceptions rule that prohibits them?