You should either have to be employed or in school to vote on important matters, especially something like an EU vote which effects the entire economy/world. Tired of useless 70 year old retired hags who contribute nothing to society getting to decide everything for the rest of the population
I don't think we should worry about adding these qualifications at all honestly. It would be better to introduce debating/political classes that teach critical thinking and reduce ignorance about politics. It's difficult to define stupidity and assess it through standardized tests. It's better to educate stupid people rather than shut them out completely.