Why was it poorly worded? The wording was necessarily simple and unambiguous. People were asked "Should the United Kingdom remain a member of the European Union or leave the European Union?". That is an entirely appropriate question. You couldn't add should the UK only leave with a deal as people had absolutely no way of knowing what any deal might look like. Plus voting to leave with a deal commits you to accepting any deal regardless of how bad it might be. Now of course the best chances of getting an acceptable deal is to be prepared to leave without one. When you go into negotiations with the EU and you tell them you won't leave without a deal you end up with the sort of rubbish that May came back with. You also can't ask should the country leave without a deal as this would rule out any attempt to strike a deal.
The issue was the UK's relationship with the EU. The question succinctly addresses this issue. Indeed, the only people I have heard who have a problem with the wording of the referendum are remainers who can't accept the result of the vote.
The question was poorly worded because it left the door open to so many questions and paths it was ludicrous. This is why, when we have a direct people's vote to something in this country, we vote on proposed bills and laws, not on a nebulous, amorphous change. "Do you want x law to become law?" "Do you want y proposal to be brought forth in Congress?" The UK should have first decided where they want to go and what they want to do, and then voted on it. They needed a plan to vote on, and then as the situation changed or developed, consult the populace as need be when in deadlock.
Apparently, however, people only wanted to vote on something once. They willingly abdicated their own voices at every step of the process after the first one and had faith in the system that everything would work out in the end, and look where that got them. A hung parliament still quibbling over what type of Brexit should be had 4 years after the fact.
Democracy is a process. It starts at a vote. It doesn't end there. Especially in situations like this, where the vote itself was so close. As much as the leavers would have liked to pretend otherwise, the fact that the vote was so close indicated that the UK was split on this issue, and that Parliament would likewise be split on this issue. This is one of the reasons why I advocated for some type of second vote or public input into the process. Lots of different ideas were floated during the campaign by all the different leave camps, and they needed to coalesce around a core of ideas. The easiest way to do that would be with another public vote, either by general election or referendum. But that was dismissed out of hand 'for the purity of Democracy' and now they have this mess.