Why do people think two lightsabers look 'weak' 'crappy' 'ordinary'?
I think that it's a challenge to wield two weapons independently of each other. Although two sabers may look ordinary in KOTOR, if anyone tried to use two escrimas, you'd soon come to appreciate the skill behind using the dominant and lesser hand at the same time.
If you don't believe me, try using one weapon in the lesser hand. It's difficult enough as it is, but one who could use both hands deserves the advantage over an opponent with a single hilt.