From the wikipedia article: https://en.wikipedia.org/wiki/Euthanasia_in_the_Netherlands, this stood out to me:
> There is much discussion about people with early dementia who have previously stated in a written will that if they ever got dementia, they would want to get euthanasia.
This doesn't necessarily mean "controversy", but is very much an ongoing discussion and speaks to a problem that euthanasia introduces that has yet to be solved in the Netherlands.
And this really is the issue and complexity when it comes to euthanasia in general: we're talking about a form of legal homicide. So under what circumstances this should be permitted is a very valid legal question. Questions about consent, state of mind, paper trails and proof of consent are also very pressing questions and it sounds like no, not ALL of these questions are currently answered in the Dutch framework.
This is also not me arguing against euthanasia. I believe that adults have the right to commit suicide by any means of their choosing (assuming they're not infringing upon the rights of others in the process). The only thing I'm saying, really, is "it's a complicated issue with lots to consider."