Too true, Odo...
I'd venture to guess that DEX is still to be considered in the equation because some Classes are more apt to be putting points there through XP that still have low REF mods and vice versa. In other words, it alolows hig REF progression Classes to need to rely less on pumping points into DEX ever 4 levels just to be quick, but those that do so, even without high REF progression, will still have good INIT.
Those that both pump DEX and have high REF progression tracks will be the quickest though...makes sense.