I agree with the nostalgia love on blue, I think if that's your basis that's cool...
However, I just can't see the argument that there's any shred of doubt about the coat's color now. Fading doesn't happen uniformly over a fabric so personally I think that's a real big stretch as to it being the "reasonable doubt" on the matter, but that's me... I, at one time, was a blue guy and now I've seen more than enough to feel it's brown.
To me, the best photographic evidence is the picture of Han in front of the lifesize snowspeeder prop (which also shows the glaring overscale size of the Snowspeeder toy by the way), which is a well lit, sound stage setting, and the coat's as brown as it gets in that picture, just like the prop that was rolled out.
Either way, I'm happy to get a blue one... For nostalgia reasons, which then I understand, I'm also into picking one up to display with the brown.