That's much harder to model, unless you have an estimate for how often the need for those other stats comes up. It's true that the worse you are at something, the more benefit you get from the +1. So if you think you're going to face a lot of fear checks, or even if it's just really important to your character concept that you succeed at those fear checks, then it makes sense to invest in Wis.
The point of my sim wasn't to argue that Str is better than the other attributes. I just wanted to add some data to the argument about the impact of getting a 16 in your primary stat.