The cost of providing an ATPL license under the new Horse **** regulations is way more expensive than the cost of a 457 visa, therefore the Visa rules.
Not sure what you mean by this but an ATPL is not required to be an FO, so unless Australia runs out of CPL holders, not likely to be any 457 visas issued to throw someone in the RHS. Direct left seat will remain a different story.
In the international market, an ATPL alone is insignificant. You will want some jet or a fist full of turboprop command.
Like it or lump it, it's the way it is. It will just make you all the more proud when you achieve your ATPL.