So, should we?
In the general case, the people should have a referendum on whatever policies they want to. These will typically be ones that the people conside important and where the government is perceived to be thwarting the will of the majority.
The way to decide if that’s true of a particular question would be to use a revamped version of the government’s epetition websites. If the number of signatures for an issue minus those against is greater than a certain number (say 10% of the electorate), then it could go to a referendum.