I both agree and disagree.
I do get where you’re coming from for sure. If both parks have a Minecraft land, some would say; why go to the weaker park of the two? The stronger park would cannibalise the weaker one, maybe other than among die hard fans of Minecraft.
On the other hand, though, I think of the success of the Harry Potter universe at Universal Orlando, with the two separate lands and upcoming third land at Epic Universe, and think that it could be a brilliant idea if done effectively. If Minecraft has separate “biomes” (based on what was said above), would a land for each “biome” really be any different to having Hogsmeade, Diagon Alley and Ministry of Magic all spread across three separate parks? Universal must make tons more from multi-park tickets since the opening of Diagon Alley.
Admittedly, I don’t think this would work as well if the second park was Alton Towers due to distance, but if Merlin put something Minecraft-based in Thorpe or Legoland, then I can see that potentially working quite well.