I think the reason for his not wearing clothes had to do with the difficulty in animating fabrics or budget. If he had a white lab coat on, I think the design would have passed for Curt Connor’s the Lizard (one of my favorite Spiderman characters).
I’m kind of the same, although I don’t think this movie did Reptile any favors. It’s a cool design, just not Reptile imo, kind of like how 2013 Riptor is not Riptor but “Stalker” (…well…maybe not that bad in comparison).