This weekend I continued my work on the epidemiology of Pathfinder, including an expansion of my programs to allow for different types of point buy. In the process I took the advice of some commenters at a related thread on the Pathfinder message boards:

I think for the non human fast fighters dropping weapon finesse makes no sense. Because they can hardly hit if they drop that. I would recommend changing it to dropping improved initiative for the fast non-humans.

In my original simulations I had built non-human fast fighters with improved initiative and weapon focus, but in this revision I changed this around so that non-human fast fighters drop improved initiative and keep weapon finesse. The results, though still not presenting a stirring defense of the decision to play a fast rather than a strong fighter, do bear out the suspicions of those commenting on that board, that for fast fighters weapon finesse is the most important feat to choose. Table 1 compares the results with weapon finesse that I generated today with the previous set of results that dropped weapon finesse in favour of improved initiative. The results in Table 1 are shown for combat with meek orcs (lacking ferocity) to be consistent with the previous post. Similar effects are observed against ferocious orcs, however.
Table 1: Non-human mortality with and without weapon finesse (revised)

Race No Weapon Finesse Weapon Finesse Odds Ratio
Dwarf 43.6 37.0 1.32
Elven Ponce 52.2 44.2 1.38
Halfling Loser 61.6 49.7 1.62

The odds ratios in Table 1 are provided to show which race suffers the most from lack of weapon finesse, and it is no surprise that it is the halflings. This is because they do the least damage, so the loss of hit chances affects them the most.

These results don’t change the fundamental conclusion that fast fighters are a very bad choice, but they do indicate that if one is going to pick this fighter build, weapon finesse is a very important feat to choose.