I agree there is a problem here with the PP... it does give people a shortcut to instant destruct of your opponent. Perhaps if the armour value of the PP could be tweaked up a few % it would help balance things out a bit more. Not against targetting the PP being a little bit of a shortcut (tactics/skill/knowledge should be rewarded) but not the major one it is now.
Alternatively, at least make targetting the PP harder. Againat most ships you can hit that PP from almost any angle. Maybe keep it weak, hell, even weaker, but make it so that you have to be firing at a fairly precise angle. No, not quite Luke vs Death Star, but at least on the right side of the target to hit it.
Caveat: Anaconda. Those things should have a massive hitbox for their powerplant, just because so many people seem to look at them and think because they are the most expensive they must be the best.