There was a rumor back in the day that Avatar was coming to Universal (replacing T2) and it wasn't met with great excitement. Granted this was before Potter showed what they can really do when they try - so the point is moot.
I know we keep circling to this but......... not all IP's can be rides/lands; just like all great rides/lands doesn't need to come from a Top 10 IP.
I think the argument is fair to be made by critics of it's drawing power - especially for spending 1 billion. I hope we can move on to better debates than just "yea, but if Universal".
The biggest problem with this IP is that Cameron didn't strike while the iron was hot. They should be on to the 4th movie by now. If they would have, and each would have done over $1b worldwide, this land would be a no brainer. Hell when this was greenlit, they were saying a 2017 opening for the 2nd movie which would have been made great co-promoting. If they are able to get the series moving again and do even half the numbers the first movie did, it'll work out fine. It'll help with international visitors as well as this was bigger overseas than it was here. Especially China.
But as to the Uni vs Dis argument, there is a lot of Dis hate here. Not by all, but it's prevalent. Some of its fair, and some isn't. I still say that if they were building this identical land in a Uni park, there would be a whole different attitude about it.