Both of those ideas are ridiculous. Anyone who works with large dangerous animals knows the risks of what they are getting into (except maybe dog owners lol.) if they don't they have no business doing it. The killer whale is being a Killer whale there is no reason to kill it for being what it is.
Turning a killer whale loose is the equivilent of killing it due to the nature of wild killers whales in relation to their social structure.
Finally the woman who was killed died doing what she loved doing and there is really no better way to go. I was a groundskeeper at a very wealthy(ie best healthcare) retirement community for a few years. Having seen what happens to people that slowly fade away is absolutely horrible. Since then it has been my hope that when I start to slow down from age that something kills and eats me. It's much better than the alternative IMO.