Possibly, Wickham did want some degree of sympathy, but I seem to have a more lascivious view of his approaching Elizabeth than many of you. I think that he was also actually wondering if Elizabeth's former attraction to him could be rekindled.

Yes, he might have been scoping out her knowledge of his dealings, but he is an unprincipled man, and one member of Elizabeth's family has already let her passions overrule her good sense. He always acknowledged Elizabeth's charms, and she formerly showed him flattering encouragement. I would not put it past him to try to set the groundwork for Elizabeth and himself breaking a few of his vows in future. It is likely that an immoral person would be more prone to guess others to lack character, too.