I just had an idea. We know Bruxish gets a new ability, Dazzling, to negate priority moves.

What if the Popplio line's HA is Dazzling too? It fits its theme. At least it'll be able to resists U-Turn unlike Bruxish since it's likely to end up Water/Fighting or Water/Fairy. With its special tank stat spread, there's a good chance it'll get reliable recovery too. It would be an amazing counter to Talonflame and Weavile, and if Fighting, to Bisharp, among many other big threat mons.