So what exactly IS the Martian Manhunter? What parts are ok to try something new and what parts have to be left alone? Because if it's all gospel, then what worthwhile talent is going to want to work on something they can't change even a little?
Cuz this sounds a lot like the "Give me something new but don't change anything" problem that STAR WARS (and many other franchises) have.
And the whole "mediocrity and negligence happen to other folks too, so it's no big deal that they happen to this one as well" mantra is not good enough. Or at least it shouldn't be.