Barret is an Ice ranged bruiser unit. With skills that can increase tankyness and a passive to increase hate, he ends up with an odd combination of roles to make him a very niche unit. However, he can still be a pretty decent support damage dealer. His main job skills have attacks that comes with some debuffs to AGI/ATK/DEF and a 3 hit attack to chain with other Ice units. If used with Gunner sub job, he can use a total of 5 status effects: Blind, Immobilize, Disable, Slow, and his LB has a high chance to inflict Confusion.
It's worth noting that his stats are kind of a mixed bag, and somewhat underwhelming. HP is more or less the same as a frontline bruiser, but ATK, DEX, and AGI are noticeably lower than even other long range damage dealers. It's less of an issue in PvE, but may struggle in PvP. And despite being the counter element to Tifa, Barret might not exactly do well against high evasion Tifa, aside from the Guts removing ability at least.
Barret received a global upgrade to some of his main job skills. They are noticeable changes, but it's unsure how big of an impact the global version fares against other units just yet.