Mag is insanely strong but lots of people just don’t read her kit. I certainly didn’t for a while until someone said Mag was shit… So then I checked out WarframeFlo’s video on her and realised she melts everything if you play her correctly. Just capture any enemy you want in a magnetic bubble and any other enemry who walks into the bubble, just disappears in a swarm of bullets. Another skill just leaves shards of shrapnel or something that also dissolves enemies around the map. Pull is fairly useless if you aren’t host, so switch that out with Nourish or something. And the other skill is a decent emergency offensive skill which restores all your shields instantly.

If your weapon is weak, she might not be so good, so use an incarnon weapon or a weapon with lots of multishot etc.