As anyone on the other thread can tell, I don't like them. But the Niles are a real threat (to anyone who doesn't know, Nile crocodile are like alligators and Florida crocodiles but exponentially more aggressive) and must be treated as real and significant threats to people and wildlife. So far it appears there's just one family line there, so hopefully they''l be easy.
As for the fences, i think WDW ought to consider large boulders, like these:
https://media-cdn.tripadvisor.com/media/photo-s/02/30/05/08/the-baths.jpg
That's the Baths in the BVI. The boulders would be pretty, and they'd be difficult to alligators to climb. They'd obstruct some beach view, but with water-based safeguards in place, the beach doesn't have to be as protected. You'd be cutting off some fish traffic and you'd be inviting more swimming, but it would limit the alligators willingness to come on to land in the specific areas where people might congregate.