Disappointed with this - Man of Steel had enough problems that needed addressing in the next film and now they are throwing in Batman ? And this does indeed feel like its being rushed and shows a lack of confidence in the performance of Man of Steel ( it may not have met BO expectations domestically but it seems to have done pretty well internationally). They needed at least one more standalone Superman film and I would also argue for another standalone Batman film to establish the tone of that reboot before throwing them together.
I agree as well. And while I have no problem conceptually with an older Batman, it doesn't make much sense within the Man of Steel universe. It seemed pretty damn clear to me in that movie that Superman was the world's first superhero. If he'd seen Batman's exploits from Gotham City on the news, you'd like he would have fashioned an alter-ego a lot sooner.
A big part of why The Avengers was so successful was because Marvel spent five movies establishing all of the characters before they threw them together. Yes, The Incredible Hulk was hamstrung a bit by the recasting and Hawkeye's only pre-Avengers appearance was a cameo in Thor, but you knew who everybody was and where they were coming from before you saw them in the same room together.
Warner Bros seems to think they can skip the build-up and cut right to the Avengers level chase.