That it is. And I think higher than anticipated by grouping people on the platform and letting them see the train come in rather than holding them until it was in place. Also keep in mind the general public only learned this was opening a month ago, with the NBC blitz--they'll need time to plan a vacation.
That said, Universal clearly overestimated the appeal of HE building 5-hour lines for it (and "re-ride" lines). I doubt that has anything to do with an upcharge factor, tho--75% of guests already can ride it. I just don't think it's that popular.
This goes back to something I said months ago--Potter may drive guest spending, but Transformers and Minions are driving attendance. Potter gets the super-fans, Transformers gets the general public. I know Disney/Lucas fanbois hate to hear it, but Star Wars Land will be much the same--never going to match Rock & Roller Coaster for sheer guest demand.
No question Diagon handles a crowd better than Hogsmeade, which helps. But it's also clear Universal misread the tea leaves somewhat. I've yet to see the outside switchbacks at Olivanders in use. I've walked through the owl rookery that serves as a line for Madame Milken's but it seems unnecessary. On the flip side, the ice cream shop wasn't built with nearly enough queue capacity--best plan I've seen is to switch the rookery around, and hope guests don't find the sight of owl guano too unappetizing.
Does nothing to change the fact Diagon is the most immersive land in Orlando, arguably the US. Just shows theme park guests can be a fickle bunch, hard to know what will suddenly appeal to them--or when they'll suddenly lose interest.