I don't even know if it's completely changing public perception of the character. I submit that Aquaman has been more popular than we gave him credit for, for a while now.
For example, if a kid is like aged 8 - 13, where have they seen Aquaman? Cartoons like Young Justice or Brave and the Bold, games like Injustice, or recent books and comics. In other words, media where he's always portrayed as a competent and worthwhile character.
The character has always had his fans in the comics. His more recent runs have gotten great reviews.
Then there are people who didn't have an opinion of the character before this movie at all. At this point, I think it's probably fair to say a lot of people seeing this movie were only vaguely aware of who Aquaman is. We think of him as this widespread joke, but truthfully, he's only really a joke to nerds who follow this stuff or people who remember Superfriends. A lot of people are seeing this movie or being exposed to the character without that baggage.
I short, DC's long plan to rehabilitate Aquaman worked.