I was under the impression that WB told Singer to cut the movie from being almost 3 hours to be shorter (I think the runtime was what, ~150 minutes?). Anyways, the RtK scene was cut and Singer essentially had to make changes that he'd never anticipated.
Singer himself has said that no one told him to cut the scenes. I wouldn't be surprised if WB asked him to, but since he's said he didn't get an ultimatum, the blame rests with him.
Also, if I recall correctly, Singer originally wanted Zod to come back as a villain, but would only do so if Jude Law took the part (which he didn't), and then he got to work on the story that became SR.
Nope. Early rumor that sprung from news (AICN) that "Superman Returns" would feature an old villain and some serious super-action. People assumed it would be Zod, but it wasn't. Just like Law has been rumored for damn near EVERY comic book movie since 2000 (Almost always AICN's doing).

. They sketched out the entire story for SUPERMAN RETURNS on a single flight, then pitched it to WB.
If Singer cut that scene it wasn't because of Brandon, IMO. Brandon did a very good job as Superman/Clark, and most people agree with me, critics and people in general. Every person I talk to about SR agree that Brandon was a great Superman. He was easily the best part of the film and an inspired choice for the role. And to some people, myself included, he was as good if not better than Reeve. Singer found the right guy.
Rose colored glasses when it comes to his acting. He's got the look, the sound and the presence, but a long way to go as an actor. Brandon Routh needs to work on his emoting. I'm not saying he didn't make a good Superman, and he had some nice moments, but I'm guessing 20 minutes of "non emoting" during a fairly subtle sequence anyway could have become a drag to open the movie.
Yes; and also because he obviously hadn't come to an agreement with Fox over the terms for the next X-movie.
That isn't why he left, though. Had he stayed on X3, the timing would have been similar. He left because he absolutely loves Superman and they paid him a TON to make it. And he's made no secret of that.
Yes, it is fantasy. But it was not out-and-out sci-fi fantasy.
Superman faced the struggles of fitting in to the world, losing Lois, discovering fatherhood; he didn't face the struggles of an intergalactic being like Brainiac, Darkseid or Doomsday.
Where is it written that he has to face an intergalactic being for it to be pure sci-fi? Or that his struggles to fit in (because he's an alien with the powers of a demigod, seems sci-fi to me) make it less sci-fi? It's a flying alien man with his alien crystal technology turning into an alien continent...
It's fantasy/sci-fi adventure.
Showtime says two pitches of Harris/Dougherty's were rejected, both including supervillains, on the basis they were too fantastical. Either that wasn't the real reason and WB wanted to get rid of the writers, or WB somehow believes SR was so 'non-sci-fi' that it would now be hard to introduce strong sci-fi elements.
I'm guessing it's more down to budget and their general approach to the character and the story.
Maybe, but I don't see that much acting needed in travelling in a spaceship and staring out of the window at the smashed ruins of the planet.
There is if you don't want to look boring as hell for 20 minutes.
I'm not going to argue why Singer cut the $11 million sequence. I don't know and I don't really care. I wish it hadn't been cut.
Right, well the use of the budget clearly didn't make an 'exciting' film. If, rather than childhood flashbacks with land purchased and fields of corn grown only to be replaced with CGI, we'd had an action sequence (tidal wave rescue, supervillain, whatever), then the film might have seemed exciting. Or at least trailers could show a bit of the action to make it seem more exciting.
That depends on what you think "exciting" is. That plane rescue sequence was among the most exciting pieces of cinema I've ever seen. The Metropolis rescue sequences were very exciting, as was the bank robbery. And Luthor and his thugs VS Superman was a very exciting, emotional sequence. I really could care less about corn. Best laid plans and so forth.