Good point about "leading" not necessarily meaning "most visited".
But in that sense Mini-Europe is even less "leading" in my opinion because very few in Europe have even heard of Mini-Europe in Brussels. I mean, I'm less than an hour away from it and I'm probably the only one in my circle of friends who knows about it. None have visited it.
Now, leading in gorgeous mini architecture I can agree with. It's possibly even better than Madurodam (have to visit irl to make that determination).