Hopes' bowling has been increasingly ineffective in the last 12 months. His last decent series was England 2009. Since then his figures against other top 8 teams are:
James Hopes from Sep 2009 onwards
So for those not clicking the linky, Hopes averages 69.10 and economy of 5.30 since England 2009.
I personally think Hopes is suffereing because of the attacking batting T20 cricket has pioneered. He used to go along under the radar between overs 15-30 and quietly strangle the batsmen at 4 RPO. Now though, there's plenty of footage of him getting belted out of the park and there's no need to feel constrained anymore. Eion Morgan for example was happy to target him at whatever stage of the innings a couple of months back.
Hopes' batting has been steady enough I guess, but it's certainly not enough to keep him in the side if his bowling is going to be mediocre. Australia already have a mediocre medium pacer who can bat - his name's Shane Watson.
As for Nannes, well I think he needs to take more Ryobi wickets - he just hasn't performed in the domestic ODIs. He's taken only 13 wickets in the last 3 seasons. Sure the guy's been injured a lot, but that's half the problem. If they are going to pick someone based on domestic form, surely Shane Harwood would be the guy to get a run.