The problem with new versions are not bug themself, but rather new implementations conflicting with old code. Its rarely beneficial to make complete save compatibility because its not actual bugs.
Personal preference, but I don't really like the change where mental stats are now tied to this new learning point mechanic. I think the old system where mental stats are raised and lowered based on what the character's daily job, and certain action makes way more sense, because how does spending time in library all day make one brave (Hermione Granger from HP notwithstanding)? I think maybe reserving purely for learning skill/spell and using the old system for mental stats would be better.
Yeah, once you have a few higher level slave set up to get you net positive gold and food, it's very easy to farm learning point by shift your slaves into library. That's one of the reason I prefer the old system other than the immersion problem. It's too easy to farm learning point after you climbing the initial curve where you only have one low level slave, and even that curve is more of a gentle hill rather than a steep mountain once you know what you are doing.
Then again, the mental stats doesn't affect jobs that much aside from high courage for hunting. So it's more of a personal nitpick rather than a deal breaker.