I've always believed that Raiden changing to a black vest and tan pants was their half-assed attempt to reference the only character who didn't appear in the movie, Kung Lao, in some small way.

I thought it was because they got tired of the bad wig he was wearing and/or they were trying (but failing) for a MK2/MKT look.

raiden did look pretty gay

When i see the trailer and Rayden wears his new outfit think that he is Kung Lao or some other character.
His new wear sucks,but is very important because make him look like a human,therefore common vests not God Vests.

The original Rayden was better, he wasent a pussy and could have (or at least tried) to kick Khans ass. and yes i no it was just a movie

Yeah, that entire scenario really sticks out in a horrible way.
Regardless of any decent logic, it's just a very obtuse way of getting a pretty damned average wardrobe change in.

There are probably a range of reasons, but presumably one of the reasons for the change was in the interest of mobility. The martial arts eventually tacked on to the character might have been obstructed, if not more difficult to achieve, in the flowing white robe. Particularly in a film that was pre-wirefu craze, and operating on a low budget.

Thought it was disappointing not to see the MKII look, though, personally.

There were a lot of other more relevent quibbles, though, I think.
I wasn't even all that thrilled with Lambert's look in the first film. I wanted something more literal in the translation, as in, the hat and all.

With the fantastic designs achieved in the games starting with MKDA, it'd be great to see the all new approached applied. That's actually something that's bothered me about the newer games.
The inclusion of the ninja costumes just really rubs me up the wrong way. With the decent individual designs we now have, I kinda prefer to view the older games with a concession that says what we're seeing is because of the limits of time/money/technology, and that they really were always wearing their MKDA/D outfits.

Unless there are attached reasons for change, ala Reptile.
Although, even then I'd lean toward something like the Shaolin Monks look - but I digress...

A disappointing effort, and personally, I think Remar would have made quite a good Fujin, as opposed to Rayden. I actually think he has a good look and decent enough presence to have been Fujin.