In my opinion, the New Mutants were written best in Chris Claremont's original run and Zeb Wells run.
These two writers gave equal attention to each New Mutant member and didn't made most of them into weaklings that subsequent writers (including Ed Brisson) did.
Post Clarement period, each writer concentrated on one or two New Mutant, I can only remember these...
Majorie Liu gave Karma character development in Astonishing X-Men.
Hickman gave Cannonball character development in Avengers.