I often recover enough MP with Siphon. It was always enough for me to gain more MP than i use with pummel and light strike.

IMO they both can stay with MP cost (even though i'd rather HP cost) because Pummel is superior than Full Swing in every aspect...half recast, damage better than the AA and nearly the same TP generated. Light strike is fine too...i just wanted its effect to last long enough for us to be able to use Light Strike again...8 seconds effect with an action that have 20 sec recast = stupid.