I find those references really corny. It's distracting. I had no problem with TDKT being isolated while it was happening and I feel the same for each upcoming Man Of Steel movie.
Now that Nolans Batman solo films are over, I had no problem with that version of Batman existing with superheroes outside of Gotham for a team-up or two. But im glad there was no hints at Super for instance. And even if Batman is rebooted, Superman should have 2 to 3 films where it's not connected to anything else during that time. This wont happen, but I have no problem with it.
If you do a solo film, they shouldn't bother with the wink winks. It's something I found stupid in Marvels movies. You're either doing the movie for the character or doing it as a vehicle to introduce other characters from your line of comics. The latter sounds corny to me. Even if I have suggested it for fun (like an Atlantis reference in WW).
There's no reason why they cant have individual films for 4 or 5 of the league members in an isolated fashion. Then use a post-credit scene or two (not every single time) to link the characters together. Post-credits are fine because it doesn't interfere with the actual film and doesn't distract you from the plot. Chances are, a fanboy will only get these little nods anyway during a movie, and that's another reason why I think it's silly.
Too much fan service.