Seen the same article and does make one wonder why the US seeing that there is an off the shelf option has not jumped on board. Googled further into it and on F-16.net there was a thread on it with one commentator mentioning that with the size of the Wedgetail there would be limitations as to what it could do.
Wedgetail AEWC - Modern Military Aircraft
Being a smaller aircraft I do imagine there would be limitation in how much power, range, and systems can be fitted into it but considering the time frame to develop new aircraft (also mentioned in the thread) logically even a partial replacement of there E-3 Sentry fleet would still be worth while because even if everything went right they would still be looking at over a decade before they got there own system all the while the wedgetail would have seen mutliple upgrades in the same time.