The fact they dropped Martyn from the Test side, I think, is to put him on notice because on form, dropping him from Tests but keeping him in the ODI side is nonsensical. You get the feeling that there were a few more reasons other than performance for dropping him and keeping him in the ODI side seems like they've taken some sort of disciplinary measure because he was sawn-off in three innings in the series and when he did get a decent start, looked solid. It's possible a reason to the two soft dismissals in the second Test might have been noted, for example. I dunno, maybe he didn't appear cut up enough about it all. Certainly he wasn't playing a missing regularly like Hayden or getting out to the same sorts of deliveries like Gilchrist. A decent score, one got the feeling with Martyn, was only around the corner.
How on Earth does one player get 30 innings to score a Test ton and look pretty out of his depth all the way yet another has one bad series with plenty of bad luck to go with it and gets dropped? No, form is only one of the reasons I reckon. And picking Hopes, admittedly a decent prospect with the bat, for Hayden; WTF?