Sacrificial offerings to the god of crossovers
When I say "firstborn" here, I actually mean the second or third string characters that you don't care about, and yet somehow think that killing them off will be a big deal. No, killing off the ones you do care about would be a big deal. Killing the easy targets you always go for just upsets the few fans who liked them and has no effect on the rest of the audience because they didn't care either, and the shock value of killing off any hero has long since lost any power because you keep doing it.
See, this is the big secret that you have somehow failed to grasp in all your history: offing Namorita or Pantha will not make your event comic more successful or more memorable. Only good writing will do that.
Rest in peace, Little Avenging Daughter. 1971 - 2006