Given the state of the U.S. and European economies, my guess would be that there is some very, very attactive finance and prices attached to new engines, so it may well make sense financially in the current environment.
The question then leads on to "life cycle cost" calculations. This is where it can get tricky because you have to make assumptions about future exchange rates. Being a control freak, I don't like the idea of not maintaining and overhauling everything in Australia.
If China vs. Japan hots up or China vs. The Phillippines, then sending stuff to Asia for maintenance is not going to appear wise.
To put that another way, unless there are scores of MRO's all over the world touting for your business all the time, then it is not going to be a competitive market and your supplier is going to have his hands around your trusting little throat pretty quick.