I would pick:
O'Keefe (or possibly one of those subcontinental-Aussie leggies)
I can't see Johnson being a sensible pick in English conditions.
Wade simply isn't up to it. Haddin is the best back up as he has
experience and can play as a batsman if absolutely necessary.
Hughes and Smith don't need any comment.
Cowan has gone backwards since his ton in the first Test v RSA last
November. It's hard not to blame the coaches, especially when Lyon,
Warner, Siddle, Watson and Wade have also gone backwards to varying
degrees, and hardly anyone has improved.
The batting really is dire. I can't believe I'm going back to Ponting but
there are no good options. Bailey and Ferguson have not done enough. In
fact, last summer's batting averages are dominated by touring players,
all-rounders and wicket keepers.
Clarke must stay at #5 where he is comfortable. The bowling is good enough
to win us at least one Test, but my money will be firmly on the Poms.
Obviously this bears to relationship to the squad that will be picked.