There are two forces- the drive towards standardisation and a more homogeneous English for international communication and the drive for national and regional models. They will continue to operate alongside each other. Many speakers already vary the way they speak according to the person they're with. It's a bit like centripetal and centrifugal forces- one driving to create and change and one acting as a brake to hold things together.
Raymott's example of How to say xxx? and others like depend of and What means xxx? are so common among some groups of non-native speakers that they will probably cross over into the mainstream.
I think the impact of Sino-English will be lower than Raymott and 5jj suggest- there will be plenty of loan words and phrases, as we have so much more contact now than we did. People were saying the same about Japanese twenty years ago and we have lots of Japanese loan words in English now and things like all your bases are belong to us, but what else? I don't see why this should be particularly different with China. There has been a huge rise in trade and political relations, and this will have an impact, but this has not been accompanied by a similar cultural exchange- we do business, tourism and so on, but I don't see why this will have much impact on English. A few thousand loan words is more likely to me, which is what has happened every time before.
PS I don't have a problem understanding most Australians and Australian English has influenced BrE- many younger speakers have adopted things like intonation patterns from it, so I don't see it drifting away on its own. Julia Gillard hasn't struck me as hard to understand when I have heard her on the news. She does sound 'very' Australian to me, but I can follow what she's saying.