At the same time, it was argued on this very site that how well a IP translate for theme park doesn't matter, what matter is how popular the IP is. I personally prefer IPs that aren't popular that I may not even fully like but still are easily translatable into theme park environments. However that isn't the case for everyone.
I disagree with the issues with Pokemon for theme park integration. Universal Creative already completed a proof of concept with Yokai Watch Walkthrough attraction at USJ.
Whoever argued that was completely mistaken: it's the equivalent of saying the popularity of an IP would determine how well it does at the box office.
But that's an entirely different calculation, some IPs (most video games) don't translate well into event movies, and some IPs don't translate well into theme parks. Every IP has strengths and weaknesses that allow it to translate into other mediums.
Pokemon as an IP succeeds brilliantly in games (the catch 'em all/collector aspect is brilliant and extremely addictive), but in many other aspects it has weaknesses.
Book-based IPs have an advantage in that they lend themselves to "event" formats like movies. Why? Because the nature of books lend themselves to those sorts of expository details in the context of grand adventures, and that's why many books end up as event movies (Jurassic Park, LOTR/Hobbit, Harry Potter, etc.). Those same event movies then translate well into theme parks because of landscapes/immersion that they offer in the context of a theme park experience.
I'm not saying you can't make a successful Pokemon attraction based on the concept's strengths, but I am saying that as an IP, it has specific limitations that others IPs don't have.
For example, Mario may have less overall popularity than Pokemon in a general sense, but it's a stronger theme park IP because it comes with various iconic landscapes like the Mushroom Kingdom, it comes with Bowser's Castle; it has iconic characters with stories behind them. It has a narrative that also lends itself to a theme park setting. And that's fine, every IP is different, every IP has a different set of competing strengths and weaknesses.
That's partially what I've referenced in a lot of places when I mention the strength of Zelda as a possible theme park IP is that it literally comes built for theme parks in that the games are largely set around a kingdom with a princess castle (which is a very natural theme park translation), and that most of the games reinforce that aspect.