There had been moves to try and shift WW away from the swimsuit long before that, Rucka wanted to give WW a more hoplite inspired look in his first run but DC only wanted it for the fight with Medusa arc.
What Guy_McNights and Garrac said is actually right. The swimsuit gets caught up in the discussion of comics portraying woman as sex objects, something the red trunks don't. There it's just a discussion of whether one thinks they're stupid or not.