I feel like all weapons look the same including legendary weapons. It's like there is no truly "unique" weapons and it's all just borderlands style guns.
1. legendary items are literallly standard equipment with an enchantment, of course they'd look the same
2. most of the unique weapons in fallout 3 have the same model as the standard version with a slightly altered texture or an attachment.
3. wouldnt it be weird if in a world where weapon attachments existed, nobody but a mailman and an old man used them?