Devs want people to be able to make choices and customize their characters. They also want the game to be balanced, thus min-maxers usually try to go for balanced builds, variating usually +- 6 from 18 str/18 agility. Because, if both options are balanced, then a build with both SHOULD be the best. In my honest opinion, that is not the case, as a more strength skewed build yields higher KDR on non-hybrid characters.
Choice and character customization is supposed to be king in this mod, min maxers only want "loL best KDR hrsdghjgnrej".