Sure, but somebody needs to care enough about that particular character and that particular agenda in order to think about including that character–including whether the audience as a whole will be confused at who that is, rather than the more familiar Iron Man or Thor.
Plus, with a character who operates on the level of Blue Marvel, suddenly you’re asking more questions about that evil army. Are they really powerful enough to keep him at bay? If he’s involved, why isn’t this over yet, or why hasn’t the story immediately pivoted to where all of the bad guys are focused on the threat that he represents rather than the characters the story is actually about.
I’m reasonably sure that he makes a blink-and-you’ll-miss-it appearance in THOR #2, though.
(Unless he’s secretly the new Thor–mind blown!)