All these accusation of Lucas using Sith Eyes because he's lazy or whatever smell like Lucas-bashing for the sake of Lucas-bashing, a trap these boards fall into all too often.

Sith Eyes were used in ROTS because they look cool.

You may say they look stupid, but you're also potentially blinded by your intense PT/Lucas-hatred. They look cool, so they put them in. To think that the audience would not understand that Anakin is evil after he killed Jedi "Younglings" is absurd, and it's completely unnecessary to accuse Lucas of that.