They can easily do this. Date's still haven't been revealed for Rock the Universe either and looking at the history of the event, they have put on the event early in years past. They could easily make Rock the Universe start on Sept 1st allowing HHN to start Sept 8th. It's going to come to a point where something has to move. HHN is a money maker for them, far more than any annual event they put on. I wouldn't be surprised if this year, or within the next few years, HHN starts opening the first weekend in Sept and Rock the Universe start becoming an end of August event. Yes that mean's it won't line up with Disney's event of the same nature, but honestly with the money that Food and Wine brings in, I could see Disney moving their event into August as well.
It just a matter of time before something happens to deal with crowds. Either start a few weeks sooner or expand into two parks. If the rumored "fourth" gate (since they are calling VB a "gate") happens soon on the new land, they might consider moving HHN to that park if it is designed bigger with more HHN locations set aside of houses. They have some things they can do, but one thing is for sure, they have to do SOMETHING. Crowds will just keep getting worse. I can already imagine what it's going to be like come the next big anniversary during HHN 30.