Looking at comic cons and fan events where people dress up, I am not seeing many females dress up in the current WW costume. The traditional seems to be very dominant.

These are events supported by fans and readers of current books. Why is the traditional costume more popular?

It's easier to cosplay material wise. Armor is more difficult to make

The basic idea and color schemes could still be done. And people have done a great job designing costume armor for decades.

Why? Because the traditional had what like 50 years of comics. The new one had 3 or 2 years. Not to mention Lynda Carter.

When a costume has IT, that's all it takes for a fan to wear it. If they like it and believe in it. Earlier someone mention how hard it was to do armor for a costume, but that has not stopped storm troopers for decades.

And newer fans are hindered by Linda Carter today? I wish.

People are wearing versions similar to the battle dress seen in the latest WW#1. Bit not so much the new modern version.

Could it simply be fans who wear costumes don't really like it?

The New 52 WW costume was so poorly designed by Jim Lee, even he can't get the details right. A lot of it is open to artist's interpretation, that's why everyone draws the breastplate differently. It changes in every book, so which is the definitive version? Chiang's double W lightning bolts, Lee's star+WW+bird hybrid or Reis' curlyQ double W's? If the artists being paid to draw her don't know, why would Wonder Woman cosplayers?

The traditional costume is much simpler to replicate and it looks better anyway. The new one is in a constant state of flux and hasn't quite gelled yet.

You also have to take into account that cosplayers unhappy with the New 52's direction for Wonder Woman may wish to represent the version that most inspired them to dress as her in the first place.