It really depends if you're coming to get a taster for future trips, a stopover on a long journey, or simply to relax in the sun. If you want to "see it all" and explore more of the UAE and the Arabain Peninsula, no, it's not enough. We'd recommend two weeks to thoroughly cover the United Arab Emirates and at least one week to cover Dubai's highlights. In 3 days, you'd still have a lot of experiences to come back and enjoy on a subsequent trip but certainly don't expect to 'do it all' or get a complete picture of what the UAE is about.