I personally dislike it when people resubmit without having changed anything, but that's just like... my opinion, man.
If you do it could you maybe add a link to the original thread as well ?
1. Many people here how may have not seen it the first time. Get their feedback, too. (This is also why I've never minded re-posts in general.)
2. Those who did see it the first time may want to see the latest version but need to be reminded. Refresh their memory. Also let them see how their input was used.
3. Feedback should not be done in a vacuum. It should be subject to review just like any other comment. I have given feedback and been asked to follow up by email. I'd rather do it here once again. Give people that chance.
4. "AskHN: Review my app" posts are not just for you, they're for everybody. Lots of others get to learn from your app and its public feedback. Don't pass up another learning opportunity for everyone.
5. If this is a repeat, include the link(s) to previous discussions. Give people the chance to see the whole picture.
I created launchly for this specific reason as a result of not being able to get good "additional rounds" of feedback here on HackerNews.