Here is why Blackfish didn't feature at the Oscars. I've bolded the part in which Blackfish doesn't meet the required standards of a documentary. This is the criteria that the ceremony requires;
"An eligible documentary film is defined as a theatrically released nonfiction motion picture dealing creatively with cultural, artistic, historical, social, scientific, economic or other subjects. It may be photographed in actual occurrence, or may employ partial reenactment, stock footage, stills, animation, stop-motion or other techniques, as long as the emphasis is on fact and not on fiction."
I personally think it's one of the best documentaries I've ever seen, if not a little outdated. If she'd have left out the fiction then a blackfish would have won the award hands down. And deservedly so. Blackfish has however achieved something extremely positive; would SeaWorld dare go back to their old methods? No. Would they ever get away with separating their young orcas from their mothers? No. Will another trainers life be lost at the hands of Tilikum? Highly unlikely. So yeah, plenty of huge plus points for Blackfish without achieving the ultimate goal.
On the Elephant story; I think most elephants are quite docile anyway, they rarely use up any energy. That will probably explain why the Busch elephants act as you've stated. Sunder is just a horrible story. Paul McCartney thought he'd freed him 2 years ago but it was revealed a week ago that he's still in captivity and still being tortured. There just wasn't enough media coverage to follow the story through and his outcome slipped the net. PETA are now involved and I hope they get some success with this one. Do you remember the story of Anne the Elephant, marc? She's was in the same situation in the UK a couple of years ago but between the tabloids and the public the battle was own and she's now living her life in a safari park.