I'd like this because it's annoying to always have to go to the zdoom.exe to play those two. so I'd want heretic and hexen to be placed in the zdoom launcher as well.
What launcher are you talking about? If it's ZDL, 1.5 (at least) does. If it's not please state which one. If it's your own, not only should this not be a feature request, but I'm amazed it launches Doom.