Let's just compile all the criticism here:
- HTTYD is a dead franchise and did poorly at box office, just make it DW-land.
- Nintendo is just a clone of the other Universal parks, and is arriving years late
- Classic Monsters are not relevant in popular culture
- Fantastic Beasts was reviled and bombed at box office and just make it London/Potter instead
If you believe the above, it sounds like they have an epic flop on the way.
Btw, making it a "general Potter" area wouldn't be that easy. Not only are the areas not the same but the time period isn't. If they're doing FB Paris, it'll be the 1920s.
This! Dumbledore is going to be a huge part of FB, and having an attraction dedicated to him would only be right. Plus you'd get a bit of star power (Jude Law).