Just came an idea to my mind, seems to fix many problems right now: High str cav builds doing too much damage, high two stat builds (24 24, 18 30 etc.) that have the most damage because of PS/speedbonus duo etc. Consequently you can increase the speed bonus again to buff archers a tad bit in both melee and ranged and fix lower overall dmg output.
Do it like all the curves in cRPG, wpf curve and alike. The more speed bonus, the higher percent of PS bonus is negated. Some won't be affected - like couch cav for example, and that is good.
Another note: positive speed bonus decreases PS bonus, negative should increase it.
Probably won't be implemented, but at least an idea worth sharing.