Back in 1943, before even I was born, a very clever chap named Abraham Maslow produced what I still think is the definitive theory of what motivates human beings.
Someone once summed it up by asking "Do you worry about the colour of the curtains when the house is burning down?"
Maslow said motivation changes as the personal circumstances of an individual change. The most basic needs are physiological (breathing, eating, sleep, etc). You can't motivate a starving man with a bar of gold but he will do almost anything you ask him to for a bowl of rice. Then comes safety (Shelter, health, etc). That bar of gold is useless to someone dying of a curable disease, but offer some medicines and away you go. The other levels are love/belonging, peer recognition and then ultimately self actualisation which is the level at where you think for yourself.
SO where does withdrawal from the EU come on that pyramid? You can't eat it, it won't keep the rain off, you can't have sex with it and I'm damn sure it does nothing to provide me with peer recognition. So the only people who will put withdrawal from the EU at the top of their list are those people who have reached the very top of the motivational pyramid, those people who actually THINK. So that's a tiny, tiny minority!
Applying the same analysis to those who claim "it's the economy, stupid" shows that this is not true either. I've already said a bar of gold won't motivate a man dying of disease or someone drowning can't be helped by a bar of gold (indeed it might be what is pulling him under).
Do the same with people who are motivated by "Freedom" or "love of democracy" a man being imprisoned doesn't have much use for a bar of gold and democracy won't cure a dying man.
"the ecconomy" is just as much an abstract concept to most people as "the EU" or "democracy" or "Freedom"
So, Is withdrawal from the Eu the MOST important issue facing the UK today?
What's the answer?
Actually, it is the economy, but only so far as a good economy creates the condition where the other needs can be more easily met. So governments need to set out its policies from the bottom up; agriculture/food, water, housing, health, defence, child care, education, representative democracy, personal freedom and a sovereign Britain (in that order).
Of course that presupposes you think the EU is a bad thing and a Federal European Superstate is not a good ideas.
If you are convinced that the EU is a good thing then maybe your priorities would be; agriculture/food, water, housing, health, defence, child care, dumbed down education, the appearance of representative democracy, personal freedom within strict rules and a sovereign EU Commission in total charge (not necessarily in that order).