I see Man of Steel 2 for what it really is ... a Justice League prequel (or an unofficial DC Trinity movie). It is DC doing a Hail Mary play in a desperate attempt to play catch-up against Marvel, who not only has the Avengers franchise, but to a degree, also has the Spider-Man universe at Sony (which is going into Sinister Six and Venom spin-offs), and the X-Men universe at Fox (which is doing Days of Future's Past, Age of Apocalypse, and yet another solo Wolverine movie). DC, on the other hand, is scared to death to do anything outside of Superman and Batman (mostly due to Green Lantern being an epic fail), so randomly throwing characters into one movie is their solution, without losing money on solo efforts.
Yes, ideally, Wonder Woman would have her own solo movie, rather than being shoehorned into a Superman sequel, which is also serving as a Batman reboot. The Hunger Games proves that an action movie with female lead and that comes with a loyal fanbase can make money, so I don't know what they are worried about. I'm concerned about how they will go about this. I'd rather they do like they did with Black Widow in Iron Man 2, where she will first appear as Diana Prince, then kick some ass as Wonder Woman. If they do something stupid like just having her as Diana Prince meeting Clark Kent or Bruce Wayne, they shake hands and one of her bracelets skips out of her sleeve and that's the whole role, I will call bullsh*t.
All that said, this movie sounds like it will be one big mess. It's juggling too many objects in the air. I won't see it in theaters, I can see this one out for Redbox or Netflix.