well actually, that would be like asking a Tahnok to incinerate a Toa in one shot. The Makuta have 42 powers, but limited ranges of all of them. They are not particularly menacing with any one of their elements, but the combination of the 43 (mask + elements, lets not forget that shadow is one of their rahkshi powers TN05) is what gives them the edge. And incinerating them with plasma might seem possible, but its not very hard to avoid. A Toa of water could thrust a wall of water in front of it that would weaken it so much as to make it too cool to be plasma. A Toa of Ice could do the same, Toa of Stone, Earth... Toa of Plasma could just redirect the blast. Toa of Fire could drain the beam of its heat. What really might pose a threat would be the magnetism and gravity. They couldn't hit em with enough magnetism to flatten them, but they could pin them while they go to slice their heads off. Sonics is one of those too. But deafening the Toa with one huge blast? The Kohrak-Kal exerted what seemed to be a large amount of energy on Lewa Nuva, and defeated him, but did not damage his hearing. The Makuta have even a less great power of Sonics than a Kohrak Kal (as a Kohrak-Kal is described by Greg as having a wide range of sonic powers. Makuta are described as having a very limited manipulation over their Rahkshi powers, save shadow). They could stun the Toa with a power scream, but not blow out their ears. Fear could also stun a Toa. Actually, fear could arguably kill a novice Toa. But fear isn't a physical force, and a well meditated Toa could overcome it. Let's see... what else... Well, anyways, my point is that Makuta may have an advantage through their array of powers, but they have only a mediocre control over their powers.