Smith and Warner are excellent ground fielders, but a dearth of options has Smith in the slips, and I think Warner is at mid off protecting his thumb a bit. Starc is ok in the outfield.
Burns, Khawaja, Marshes, all pretty average. Guys who are reasonable fielders elsewhere are being shown up in the cordon also.
You take good fielders for granted a bit, and Australia had a run of always having a few high quality fieldsman around. Taylor, Mark Waugh, Hayden were all sensational in the slips, Ponting was an outstanding fieldsman especially in short (he just always hit the stumps, instinctive fieldsman), obviously Symonds was good, but pretty limited test career, Clarke was n excellent fieldsman, particularly in his younger days. Current lot is quite poor - a lot are inexperienced I guess at playing under the pressure of test cricket, but it is disappointing.
Nevill has made a huge difference behind the stumps though, keeping very impressively.