Boston has had an app like this; it's called "Citizens Connect."
Essentially, it's a very half-assed ticketing system. You open a ticket, and that's it - you can't provide any further information, or challenge a request, or re-open it. There is only one action city worker can do - "close" the ticket. About the only thing they got right was not forcing people to select a category; a team of staffers handle that.
What people quickly discovered was that city workers would just close tickets, regardless of whether the work actually got done or not. So, what you saw increasingly were tickets that said "STOP CLOSING MY REQUESTS WITHOUT FIXING IT."
That said...it beats Cambridge, MA's system, which has horrendously poor geotagging and only accepts requests in a few limited, narrow issue categories.
I have three or four of these apps for the various cities I spend time in now. It's stupid. There is a national service set up, but cities don't like it because it provides a lot of reporting to the public. City workers don't like Joe Q Public seeing how long requests take to clear and stuff like that. Makes 'em look bad....