The prequel Jedi robes may be extremely ugly but I'm pretty sure that (aside from the higher cut required for wire-fu) they were essentially what Lucas envisioned for the Jedi uniform when he made SW 1977.

ROTJ was the film that really introduced darker-colored, more "utilitarian" clothing to the Jedi, and then only in Luke's costume. The TPM concept artists initially ran with this idea--Doug Chiang lobbied to have Jedi in black body armor--but ultimately this lost out to the "just do it like ANH" idea.

I would argue that the confusion between Tatooine desert clothing and Jedi robes goes back to the original film. After all, Ralph McQuarrie on SW 1977 was told to put Ben Kenobi in a "Japanese kimono" apparently because it was the costume of a Jedi, and the final cut of Alec Guinness's robe is almost exactly that, in weathered white fabric with a brown undershirt.

On the other hand, John Mollo did draw concept art of Obi-Wan in a more typical Tatooine-style farmer outfit with a Japanese shirt, a vest and leg puttees, much akin to what he drew Luke wearing. This ultimately wasn't used.

(Mollo also put in a nice detail on his drawings of Ben's Jedi cloak that I liked very much: a silver tassel on the point of the hood.)