Form is important, but it's also very changable. I actually think it's impossible to say "X batsman will have a good/bad series because of his current form", because you have to begin or end a form slump at some point. Look at Martyn and Gilchrist last Ashes, for instance. At most it's a factor in a prediction, it can't be everything.
Let's not forget that Ponting had a brilliant run of form leading up to taking over the captaincy, then an extended slump. He only made 3 centuries between the home series against India on 03/04 and the start of last summer, and just one in the Ashes and nothing in the Super Test. So realistically, he was in pretty poor form before the start of last summer as well, but it didn't really have any impact. I think Ponting will have a good series because he's a top class batsman at the peak of his career and I think he'll find touch again when it matters, not because of his form.
But seriously, his form isn't that bad. His last test series he made a match-winning century, and all he's played since then is ODIs, and he made two 50s in the CT and had an average series. Even if he fails for Tasmania in the Pura Cup game, I'm not that concerned.