I enjoy the Action! System for its simple Attribute+Skill+3d6 mode of resolving actions. It's a pretty straightforward mechanic that tends to encourage the development of skills instead of increasing attribute scores. In my old D&D days, the only way to become significantly more powerful in combat was to increase your Strength score, not become more skilled with a sword.
As such, the Action! System has a problem with attribute scores, especially the STR score. I expect the score to express some kind of relevance to another score. For example, if a person has a 4 STR and another has an 8 STR, how much stronger is the person with the higher score? Is he twice as strong? Is he some multiple times stronger? What I found with A!SCRv1.1 is that double the STR score could make you anywhere from 1.5 times as strong to 100 times as strong. It didn't make sense to me that a STR point could increase your strength by double in some cases, but 10 - 20 percent in others.
The solution was to recalculate the scores based on a logarithmic function. The results appear in Lenga 02 - Attributes and Lenga Appendix A - Extended Attribute Tables. The result is that a character with twice the score of your character will be about six times stronger. A character with twice the INT score will be about twice as intelligent. A character with twice the REF score will have approx 3 times quicker reflexes.
MOV was also a problem. The example in A!SCR of someone with moderate scores (Swingin' Sam) allowed him to sprint at world record speed. He could have run the 100m in less than 10 seconds. According to the rules, he could have kept up the pace long enough to finish the race. A person with all 10 scores could sprint at almost 50mph!
The solution was to change the formula of the MOV score to be an Average of REF, STR, and HLT. There is also a trait for Fast Mover that allows for a direct increase in MOV. After all, the fastest runners in the world do not have a 10 STR, though they tend to have high REF and HLT.
Look for more details in Lenga, specifically chapter 2 and Appendix A.