[Kissmequick]

Well the spells he does do are pretty powerful. He beat a Balrog, that's quite good as wizardy things go.....

Ofc, the geeky answer is - he's a Maiar, or demi god, though on this plane he loses much of his power, and has the frailties and weaknesses of men. He's not supposed to interfere by force ( hence he doesn't use his spells very often) but by influence.