Re: SPD inflation obesrvation & solution
I've always thought of SPD as being genre specific as to what are the benchmarks are and definitely tied to the characters' combat ability. In a standard Superhero game, the characters are comic book/graphic novel Superheroes they are by definition above and beyond what normal (including athletic and Olympic caliber) humans are capable of. Batman is not an ordinary human nor is he equal to an Olympic athlete, he is superior. The only real human being known who had nearly the combat training he has had and was as much of a natural athlete was Bruce Lee, himself a legend and known for displaying abilities far beyond those of any average martial artist. Batman a SPD 7? I can see it.
In a standard Heroic level game, the characters are individuals who are exceptional but are not as so far above what is average as are Superheroes. Many of these characters have some combat training and/or combat experience in their backgrounds which gives them their enhanced combat reaction speeds.. Some classic examples would be Zorro, Robin Hood, Dirty Harry, Zena, etc.
These folks tend to be around SPD 3-4.
As player or GM I haven't had many problems with player characters wanting to raise their SPD unless they are feeling consistently ineffective in combat. That seems to be the most often reason for SPD inflation.
Of course all of the above is IMHO