Yeah, as you field bigger weapons and start facing enemies with higher guts, there's definitely something to be said for going for outright cockpit destruction instead of taking out the pilot with little injuries here and there; although with anything less than an AC/20 it will still take at least 2 direct heat hits to destroy it. In the beta, called shots to the head could get as high as 13% on a side shot from an 8-tactics pilot. Who knows how high a 10-tactics pilot's called shot head accuracy could get?
So long as you can only take one damage from a given mech in any firing action (from weapon damage), it basically means there are severely diminishing returns for using high volume weapons, because the additional head hits won't matter as far as pilot damage goes. Would be easier to just go for a double-leg, if the called shot on a leg with a tactics 10 pilot is above 50% in a given angle.