[BirdWatcher]

Also completely anecdotal and not meant as hard evidence of anything:
but, in my current fictional save one of my young speed demons in the most recent season completed stole 25 bases while being caught just 4 times (86% success rate) while a slightly more established base-stealer on my team stole 43 while being caught 17 times (a respectable 72%.)

That's just two guys in one season and certainly we are not talking about the number of attempts and successful steals that you are referencing with Rickey Henderson. Still, when I read this in your statement above- " But in this game getting 80% efficiency while trying to steal more than 20 times is nearly impossible, because of the game's mechanics. It really needs to be updated in this area."- I have to think, based upon my own admittedly limited experience, that this seems like a real stretch. I don't see this as anything close to being an impossibility. From what I've seen, depending of course upon season modifiers/strategies, etc. it is something that absolutely happens in OOTP.