Heh - yeah. That was fun. I was focused on like 8 billion things at once - I was watching an excellent production (with perhaps the greatest set I've ever seen on the college level), I was focused on my fiancee sitting next to me, AND I was working on the exponential growth model and trying to make it limit without resorting to population growth model (which isn't as stable as I'd like for the skill set equation).
You're an insane frakking nerd. Period. End of story.
Over all, skills will grow over time (with use), but as they increase, their growth will decrease. For example, if it takes two days of training to get from 40 to 50 in a skill, it will take four days to get from 50 to 60. Eventually, it will naturally platue at a 'max value'. this max is based on each race. Let's say a human's 'break shit' skill is at 95 (max 100), and a Sooni's 'break shit' skill is at 95 (max 200). It will take much more training for the human to get from 95 to 98 then it will for the Sooni. This is because the Human's near his limit, while the Sooni's got quite a ways to go before she's close to the 'knife edge'.
As an additional idea: what about special skills or abilities that are unlocked for a Player absolutely (or very closely) maxing out their skill in a particular area - they become a Master in that area, and gain some advantages (and possibly some disadvantages) for succeeding so well in that area. Obviously, each individual Player will be unable to max out some particular skills (for instance, I could never max out a Medicine skill or something like that, but I could max out a Computer skill); this would depend on intuition and such largely, so that people have to think about what their character's good at before trying to max out that ability. Additionally, once the Player has reached Master status, it lasts for a while before the decay starts to kick in so that they don't have to worry about "oh noes, I have to find somewhere to use my ability before I lose 2 points and lose teh madd skillz!"
Thoughts?