Well, I dunno. Black Widow actually was never really called an assassin in her own comic before this current solo (the only previous occasion was, I think, a recent arc of Kelly Sue Deconnick's Avengers Assemble), and this solo is her longest-running solo feature to date, by any count. I don't entirely agree with it, but that's the truth of the thing! There's a lot more death in comics these days anyways. I think it's part of the trend.
Elektra is actually the only book out of the ones you mentioned to be canceled (Gamora and Angela haven't even come out yet), which kind of came as a surprise anyways since previous Elektra books did pretty well and this particular book was acclaimed.
it's a little too xena warrior princess for me. complete with plucky female sidekick. but it's only a first issue, so maybe the creative team will wow audiences soon.
JIM was excellent. I have every issue and tie-in to that story. It was one of my first ventures into the world of Asgard and man what a ride!
I thought Angela was awesome in her first issue. I have full trust in Gillen to make an incredible story and the art was awesome as well. In regards to her assassin-ness, I am fine with it. While I wouldn't like to see it in real life (I am actually quite the pacifist), I like the drama when I am reading.
I hope this comic goes on for a long run.