Bolin is a decent earthbender, but no he is not a master. People are forgetting that whenever he and Mako have to fight anybody who isn't a low-tier baddy they have a hard time or lose. When Mako and Bolin fought the twins they got their asses handed to them if I recall correctly. They can hold their own in a fight ok, but ultimately will lose or need to be rescued by Korra Sue.
With the gaang, everybody in their had something Aang couldn't do or they were a better bender of that element that aang would be within that limited time span. I understand that Korra has been practicing her bending since she was a small kid, but it removes the need of a gang. In fact she doesn't even use water bending that often and that's supposed to be her forte.
Mako has lightning bending, but instead of making him use that more often he seems to forget it exists, and I doubt everybody he fights will know the redirecting style that Iroh came up with so the only excuse of not using it to stand out is because it's deadly and this is Nick. Bolin should've had metal bending, but I'm hoping that with the discussions of 1 in a 100 benders and bla bla, not to mention that everybody else in the police force can metal bend, that they'll decide to give him something like lava bending.
As to the family being evil, lol doubt it. Maybe Lin's sister is in on it willingly or not, but the children are not in it. The daughter looking at Bolin wasn't anything more than a girl looking at the guy she likes.
