I mean in all honesty if they keep announcing more characters (like MM, Flash etc) then I think it's pretty safe to let go of the idea that this is Superman/Batman.
I'm still pretty sure Superman and Batman will be the focal characters but it's possible that this has turned (or always was) a Justice League film.
Complaining at this point would seem a bit futile. Despite my reservations it's hard not to get excited for this. Snyder handled Watchmen great and I do trust that he'd be able to balance the screen time for these characters pretty well if given the chance.
Characters like Flash, MM, and now Hawkman have not been officially announced as of yet.
The official announcements about this movie have labeled and described it as a Batman/Superman film. Then, it was announced that an actress has been cast as the character of Wonder Woman. There was no modification of the description of the film by the studio. There has been no backtracking to suggest that this will no longer be a Batman/Superman story and that it will suddenly focus on the Trinity instead.
I just find it funny how people can't accept other heroes or characters from the DC universe as minor characters or smaller supporting roles. Wonder Woman is cast, Flash is rumored, and all of a sudden this film is being labeled as a total cluster**** and NOT a story that can focus primarily on the relationship between Batman and Superman. Jor El, Colonel Hardy, and Perry White were featured in several key scenes in MOS and were all technically working for the greater good in some capacity. Should we have considered that a team up? Did Superman and Lois lose out and get shafted because of these minor characters? (two of which will not be in this new film)
When I think of TDK, I can surmise that both Bruce/Batman and Harvey Dent featured most prominently story-wise. They were both the primary protagonists for much of the film (until Harvey's turn), and they both had a fair of amount of the overall screentime. They were mirrors of one another, essentially, and both heroes in their own right. However, Jim Gordon also played a big role in the events of the story. Alfred and Lucius were present throughout and played roles in the outcome (aiding Batman along with Dent and Gordon). Rachel's story (and death) was an essential part of the plot. On top of the good guys, there were also several antagonists featured in the story -- Scarecrow, the Chechen, Maroni, Lau, the Joker, and eventually Two-Face.
So I'm wondering, were Bruce and Harvey's character arcs completely undermined by all of these side characters, several of which I didn't even mention? Would most people here NOT consider TDK to be a Batman film?
My point is that this worrying is premature and unwarranted. All of these blockbuster superhero films are technically ensemble pieces (even the solo adventures) with bloated casts and a plethora of characters. Each character is a small piece of an inter-working mechanism that helps push the primary plot forward. Recognizable roles like WW or Flash being cast does not automatically equate to this being the next Avengers with 6 protagonists garnering equal shares of screentime and story focus. If anything, it equates to a desire on the behalf of Goyer/Snyder/DC to begin drawing more characters and ideas from the DC comic mythology in an effort to build this new film universe properly.
Thankfully, DC is not trying themselves down to a formula of solo film - solo film - solo film - Justice League. It seems they're trying something new by featuring characters in a smaller capacity who will go on to play larger roles in this universe as it continues on, both with solo films and team-ups. I, for one, am happy to be getting a look at our new Wonder Woman in this film, however small her role might be. If they play their cards right with her (and any other side characters they bring in), they'll leave audiences clamoring to see more of her in her own film.