Dazzler was recently recruited by SHIELD to hunt down a bunch of rogue X-Men (Cyclops, Emma Frost, Magneto, and Magik). Pretty quickly, Dazzler was drugged and kidnapped by the mutant shape-shifter Mystique and then impersonated for months. Magneto eventually rescued Dazzler from captivity. And then Dazzler realized that nobody had even noticed that she'd been replaced.
Which led to her quitting SHIELD in disgust. Hence, I guess, the new look.
I'm not a huge fan of the new look. But maybe it will grow on me.
What do you all think?