Sydney fundamentals are still strong. This recent blog post helps to put things into the broader context.
http://petewargent.blogspot.com.au/2015/05/macro-prudential-and-sydney-property.html
Yea...the fundamentals in syd are very strong and non transient, which limits the severity and duration of any future correction; however there will be a correction, just that it will be more muted.
Sydney's main issue is affordability - cg outpacing salary growth and that is a big driver for sydneysiders to look elsewhere.