(I don't know if I would call that clarification... It was literally a one word response.)
Well if there's no restrictions, then I want to just chime in here...
I love history, but if there's one thing I've never been a fan of is pigeon holing nations into certain roles, long before they demonstrate that they are competent in those roles. For example, Spain getting national ideas focusing on colonialism, long before they prove they're actually capable of it. So, the logic of the ideas, is that "well this is what they did, therefor in game, right now we will decide this is what they are destined to do.". For me, as a player, this feels kind of empty... It's what I prefered about EU3. It wasn't predetermined, you became the nation that you wanted to become, not the nation that is determined by history.
The nation designer, for me, doubles not only as a way to explore new nations in new regions and throw a monkey wrench in the whole thing, but also as way to "redefine" the destiny of already present nations, like Castille. What really prevents Castille from being a land power? It could have been possible. Maybe we can change Frances ideas to be more colonial focused... or finally make a another nation in Europe that can actually rival Prussia... I've never liked the idea of just handing over powerful ideas to history's "winners" and everyone else just needs to accept their place. If anything, I find that it betrays the idea of history. History is about the circumstances surrounding events that have passed. To build the game in such a way that irregardless of the circumstances, those events come to pass no matter what, seems... unrealistic and ahistorical actually.
EU, in my opinion, is a history sandbox game. It gives us all the historical context for us to develop our own narrative and it allows us to use that historical context to build and experience our own history. In some ways you want to the game to "stick" to history, so you can feel good about defeating the Ottomans or France, but over time you also don't want every end game war in Europe to always be about going after France... there needs to be some flexibility.
I have nearly 1100 hours on EU4. I'm ready for a custom nation designer so I can play fictional nations in different contexts. For me, history is fun because sometimes it can create interesting "what if?" discussions. A feature like this adds a ton of replayability... If there are people who don't wish to use it they can simply... not use it. I purchased Conquest of Paradise because I wanted to play and New World nations like Canada and the United States... and I did, but I never used the random new world feature, but I never complained about it... I just didn't use it and it was never a problem... I've never understood the mindset behind complaining about a completely optional feature.