For mine I reckon Tait is to erratic to take to the world cup and most teams are used to 140-150kmhr bowlers. He bowls too many wides. I think I'd rather have Siddle as he can bowl accurate 140kmhr and also bat. No idea why he wasn't in the one day series, is he injured?
The selectors would be mad to select anyone who is slightly injured, its better to have healthy players. I seriously wonder about selecting Ponting & M Hussey. Aaron Finch looked like a quality batsman during the 20-20 games and he also wasn't tried during the one day series.
