When a business like amazon do something new, expectation goes high and higher. Being a true turker for last 3-4 months, I expect amazon will add more payment options for us, considering the global perspective. Existing system is working -- but it's too slow and we should have faster options definitely.
I think that rather than more payment options, we'll see withdrawal to a bank account become an option in other countries eventually. I'm sure they'd prefer to build on their own payment system rather than to support someone else's.