I'm in similar shoes. Been working on an app for about 2 years and submitted it a couple of times after major updates in order to get feedback on the changes. After the original submission it started to just fall off the front page with out any votes or even many click throughs (according to Google Analytics). Which makes me wonder if it's impossible to resubmit something -- even if the old submission is months or years old or if it's been deleted.

Even today, in this atmosphere of upvoting Show HN posts, it fell right off the new page.