I have had a few addition rejected, only to find it was a mod mistake after I send them photos of the item or provide extra information.
It would be nice if they had the option to "request more information" to avoid having to submit the same item multiple times
they should be sending you a PM along with the rejection to explain why it was rejected, but maybe this would be better with a change in policy? it would be simpler for staff to simply send the PM first to discuss the issue they have with it, then if it turns out the submission is correct they can approve it without needing it to be resubmitted.
it would be nice to have the option you mentioned as well, i just think staff doing things like i mentioned above might be a good hold over until they can implement that feature.