Why would you want all four series to have the same tone? Wouldn't that be redundant? If you've got four different shows, then they should be different. They should complement one another. If one goes unusually dark, there should be a lighter one to provide balance and relief.
I mean, it's not as if Daredevil is an out-and-out comedy character. In Waid's interpretation, he's a man who's been through several different hells and come out the other side, and has chosen to define himself by the latter rather than the former, to use optimism as a source of strength and a defense against despair. I have no problem seeing such a character sharing a universe with a different character whose life is in a darker place.
