Melkor's depiction by artists: Flawed?

[Belegorn]

Melkor was grandiose. His helmet, as the Morgoth, was so heavy Beren could not lift it [Lays of Belereiand, 8.4136-4137], and he had a scar and limp [12.3604-09, 3615-3617, 3632-3634]. I agree that terrible does not necessarily mean he had an ugly countenance. Melkor's physical form in the beginning is described as:

Originally Posted by Silmarillion, p. 12

because of his mood and the malice that burned in him that form was dark and terrible. And he descended upon Arda in power and majesty greater than any other of the Valar, as a mountain that wades in the sea and has it head above the clouds and is clad in ice and crowned with smoke and fire; and the light of the eyes of Melkor was like a flame that withers with heat and pierces with deadly cold.

He is also said to have walked around in various "shapes of power and fear" [p. 34] I'd say he was more of an intimidating figure than an ugly one.