Okay, so if Nintendo goes into Kidzone and the MIB plot we could potentially lose two or three house locations (Sprungs and Parade). Rumors are also flying that there will be a Disaster replacement soon so that potentially takes another house location away. There are also rumors of a Twister replacement but that one may not lose us a house location so much as they would have to reroute the queue location (assuming they want the attraction open for HHN). Worst case scenario, we lose four house locations in the Studios.
Moving over to Islands, there are rumors of an upgrade coming to Marvel that may add a new ride so, depending upon the footprint of said attraction, we cannot absolutely count on the Carnage Warehouse. The Triceratops Encounter trails are supposedly going to hold a JW raptor meet and greet so they might be out as well. The other four locations (Discovery Center, Thunderfalls Terrace, Popeye and Bluto, and Poseidon) are currently 'safe' but in a few years, who knows?
With the dwindling house locations it might become harder to put on the event. Add to that the fact that having the event in two parks may not be profitable enough to justify shutting both parks down for the event.To me this begs the question, at what point does it become more costly to put on HHN than to not?
Personally, my friends and I only visit Universal yearly due to HHN, so not having it would remove our incentive to visit the resort every year. Remove HHN from the equation and you have lost yourself six regular visitors. Does Universal/Comcast know that an audience like this exists? Better yet, do we out of staters represent a large enough segment of their population during Sept/Oct for them to care?