I don't see this so much for posting as I do for creating a new topic, especially a game topic. Every community I've been through so far, not one of them has added this feature. When you are creating certain topics (such as games), there are so many rules to keep in mind of, and sometimes trying to create that topic only to realize you are missing some key pieces, or have to run off to work, you're only option is to:
A. Scrap it and start all over or
B: Post it anyways and hope you can fix it up before it gets removed and you'll have to start all over.
The only downside is that you'll have a people begin a topic, save it as a draft, forget they did and start all over, or abandon it completely. Either way, the topic continues to float around as a saved draft, which can pile up quickly after awhile. So maybe if something like this were implemented, it'd have to have a timeframe from which it needs to go from saved draft to official topic before it gets dumped.