I like the New Power outfit as well. It gives off a sense of completion and distinction when compared to the more exposing and dynamic basic forms. Plus, the more uniform get-up better presents the Guardians as a unified force made of five distinct powers.
Now if only the five did things like put their full power into a single element or cross the streams like they did early on in the comics run. Well, using the weapons in tandem or singing people out of existence also gets the teamwork message across but it never hurt to resort to the classics.
My tangent aside, I like this work from two years back. The stoic expression betrays Will's brash and determined disposition but it's easily overlookable because the balance of colors and majestically radiant light definitely show that she's the leader and one girl you should never mess with. Plus, the Magic Bolas look plain awesome.