Who doesn't love a good superhero theme! I actually want to share my thoughts on these hero-by-hero, at least for DC to start with.
Superman
John William's original theme will never be topped. Hans Zimmer's Man of Steel theme is nice, but I commend Danny Elfman for saying "Nah, this is the real one" and sticking John's theme into Justice League. That decision may have irked some, but I was totally the target audience for it!
Batman
Again, Danny Elfman's original theme will never be topped, and I loved his inclusion of it into Justice League (although it was a bit more self-servicing this time). When it plays as Batman shows up by the bat-signal is one of my top film moments of the decade!
Hans Zimmer & James Newton Howard's theme is cool for the Dark Knight Trilogy, but Hans and Tom Holkenborg (Junke XL)'s theme for BvS was just...bizarre.
Wonder Woman
I think I'm in the minority here but I kind of hate Hans Zimmer's Wonder Woman theme. I would much prefer she get a more whimsical theme akin to John Williams' Superman theme than the "badasser-than-thou" treatment she got in the film. Going back again to what Danny did in Justice League, he tried to dial that back by giving it an orchestral treatment, replacing the electric guitar riff from the previous films.
Green Lantern
This just about says it all. James Newton Howard dropped the ball among balls with this one. I still lament the fact that we've never gotten a great GL theme to go with all the others!
Aquaman
This one, however, by Rupert Gregson-Williams, knocked it out of the park, a big surprise from a guy who was to that point mostly known for Adam Sandler crap.
Shazam!
A nice little tune from horror-movie veteran Benjamin Wallfisch, but hardly a great superhero leitmotif that can be used for the character.
As for the TV shows, I certainly like the themes, but I still don't think either Danny Elfman's 1990 Flash theme or Blake Neely's 2014 theme are equal to a great cinematic theme for the character like the ones above. That one, I hope, will come. Given director Andy Muschietti's history, it will probably be by Benjamin Wallfishc.