It’s more like 4500m deep, which is certainly very deep, but well within the depths that flight recorder are supposed to be able to survive (they are certified to at least 6000m). It is however pretty much the maximum depth that the ROV Australia has sent down there is certified to operate at, which could make things awkward.
What’s interesting about the Wharton Basin is that there isn’t much info on it. There was a huge quake 7.8 magnitude quake in 2000 which should have generated some interest from geologists for study.
http://adartonamap.wordpress.com/2012/02/03/the-wharton-basin/