Hello and greetings from Munich, Germany!
I thought I would share my thoughts from the perspective of a European or German. The announcement that Universal is coming to Europe has also caused a lot of joy and discussion in europe forums/communities. There is a very large theme park community here in Europe, we also have a lot of large parks and many many more (very) smaller ones.
I think the choice of Great Britain was a very good one. No matter which country in Europe, most people would probably have come by plane anyway. The flight network in Europe is far too well developed for that and cheaper than travveling with the train or even car. Traveling by train from all over Europe through the Eurotunnel is still possible and well connected.
Other points: Great Britain is much further along with cashless payments. Germany for example, is very backward when it comes to cashless payments. And there are way too many regulations for such big projects

The UK never had the EURO as a means of payment, which is definitely a disadvantage, but as I said, cashless payment rules here.
Secondly, in my opinion, it's the language. English is simply so widespread that most people in europe can at least understand it to some extent. It is THE common communication option between countries and languages. Or at least know someone in their immediate environment who can speak it well. Anyone who has been to Disneyland Paris knows what I'm talking about. You simply don't understand anything here (even the staff don't speak English well enough) and in the attractions you're more likely to be confused about what's going on. So only French people understand here. It would be the same for parks in Italy, Spain or Germany. You can clearly see that at EuropaPark. They try to combine German, English and French. Sometimes even more languages. But this might be also hard for people from outside germany. Also I think you do not have to translate everything to a specific language (BTTF, or any other IP) because you can already take what you have.
I'm really pleased that I no longer have to fly all the way to Orlando for the Universal Parks. And that's how a lot of theme park fans in europe see it. It remains to be seen whether the annual millions will be realized (also how the economic or political situation develops in europe). In general, however, I see the project as very positive.