The snag with requiring more than a certain percentage is that one question is the status quo, the other change, they are neither equal or similar. So a straight majority is the only fair way.
Surely the opposite is equally valid - that to move away from the status quo should require more than a simple majority.
Why? The first referendum on that issue in 1975 (though it was only about joining the EEC, not the "superstate" EU) was decided by a simple majority, so it is only fair to do it in the same way.
The same argument applies as to whether a simple majority is sufficient in a plebiscite. Just because we set the bar at 50% in 1975 does not mean that it was the correct thing to then much less now.
However it probably was more reasonable at the time given that we had only been members for three years, so the "status quo" was far less established.
Ultimately it depends on the circumstances, especially on whether the status quo is beneficial, neutral or harmful, and that itself might be nuanced or contested.
In all it shows that holding referendums is quite a poor way to govern.
And who would decide which way is "beneficial" ? .
That was precisely my point when I said that might well be nuanced or contested and demonstrates why policy making based on the result of a popular vote might not be all that good an idea. Yes, I can see that you could respond to that with "well the only thing to do is set the bar at 50%" but I don't particularly agree that it is a good solution - at least not 50% of the vote cast. 50% of the
electorate I would be happy enough to support.
Whatever you think about the vote it cannot be argued that it has not had a profound impact on UK and EU politics. Whether that will be a good thing in the long run remains to be seen.