I think that power swords and chain swords should shift around bonuses, so power swords scale penetration with

strength and chain swords scale damage with strength.

The way I view this is that you can't do more damage with a chainsaw by swinging it against someone harder - the damage comes from the lateral motion of the teeth, not the force of the user - just like you don't cut wood with a saw by swinging the saw at the wood like an axe. However, you can penetrate armour better with a chainsword by being strong enough to keep it in one place and not sliding around (just like you need to do with a tree). Power swords are the other way around - you can do more damage by swinging them at someone harder (they work on the principle of an axe, not a saw), but their penetration comes from their powerfield which parts molecules and the powerfield isn't made stronger by your arm.

That's my rationale anyway and it's been useful for me.