The Concierge said:

Y'know, I have to chime in here: As far as I remember, Ben's costume originally was designed to be reminiscent of a samurai's garb, ie, a warrior's. The outer robe is fairly generic (the jedi being rather humble in most regards), suited, I think to disguise...notice Ben is always very well-wrapped in public. In short, Obi-wan's costume was always meant to be his Jedi outfit!

I simply don't agree. And frankly, it would be stupid for Obi-Wan who is supposed to be in hiding to wear his very obvious Jedi robe and get sniped by Boba Fett. It's stupid. Of course, then you have to explain why they brought Luke to the very planet Anakin was from, and the very house that Anakin visited where he knows the names of everyone who lives there. It's a lot of stupid.