I wouldn't mind seeing that in a JLA comic. But I doubt we will. It is rare to seeing any kissing in it. I know Batnan and Wonder Woman have kissed but that lead nowhere.
Maybe a Vertigo comic might have shown something like that. But not main stream DC.
I don't think I would agree with a lot of your comparisons. Savage Dragon is a totally different character than the Hulk. Both are green and strong but there the similiarities end. The same can be said about the New warriors and Teen Titans. But the Authority and JLA. As you said Apollo and Midnighter are suppost to be gay Superman and Batman. There powers are almost the same from the little I've read. The Authority has a magical Doctor similar to Dr. Fate both are even called Dr.'s. The Authority has a winged girl like Hawkgirl or Hawkman. And the Engineer I'm not sure of her powers but she looks a lot like a female version of Captain Atom.