I don't think it would easy : it was part of the roman court, granted, but didn't was ranked high in the clerical hierarchy and had little support among Roman nobility or Capetian court.
You'd argue that Hadrianus V wasn't that high either, and still ended elected. But there's a lot of nepotism at work there, that Martinus wouldn't benefit.
In a similar note, Johannes XXI wasn't that issued from traditional circles, but beneficied from being a cardinal.
(As an aside note, Martinus was most probably Czech, not Polish, in spite of his nickname)
Now, what if he's elected for some reason (maybe Guelf and Gibeline situation get councils even more stuck and Martinus elected as a compromise?)
I'd think he'd have a similar policy than his predecessors (especially Clemens IV and Gregorius X) and successors eventually, though: support of Angevine interests in Mediterranean, conciliant with Habsburg.
But really, his non-belonging to traditional circles and absence of real relations with traditional support bases are going to be huge obstacles.