I think the reaction to Teela's outfit is moreso a reaction to He-Man covering up. Teela's new costume is less skimpier than her Battleground Teela, so it's probably not the skin itself. Since He-Man isn't showing skin, Teela who normally wouldn't look out of place is now stereotypically not covered up. It's like taking the normally loincloth, furry boot wearing Conan and metal bikini wearing Red Sonja and dressing Conan from head to toe in armor, while Red Sonja is still dressed in her chainmail bikini.
I also believe how Teela's new look is perceived is dependent on the artist. When Pop Mhan draws her, she's more vanilla or less sexualized than when Ed Benes draws her. Ed Benes is famous (or infamous) for his sexy women.
Strangely enough, She-Ra retains her original look. No New 52 outfit there. I wonder why? You can change He-Man and the other vintage characters, but not She-Ra?