Rogues play this and the Thug. Every time they attack, they can create a minion or buff an existing minion.
This will clearly see play, and you know other Pirate cards are coming.
The problem is. at 2 mana. It is more clunky than Hench Clan thug is. If you have to hero power on 2, then play this and attack on turn 3. That is ALOT worse than Hench Clan Thug. So Even Rogue seems like it could make it less clunky so you can hero power on 1 then play this on 2. But then you can't play Hench Clan. I agree with whoever said that it almost seems better in Wild Warrior because of N'zoth First mate. But the 2 drop slot is already really good in wild pirate warrior
Coin this, into hero power, into Captain to give all +1/+1. If somehow all your minions are alive until that moment (can happen against slow decks, e.g. wild growth, armor up), you will have 2 3/3s and 2 2/2s.
Folks keep saying Hench-Clan Thug, but really it's more like Primalfin Totem. HCT grows in a way that can often outpace removal effects. Sharkfin Fan, like Primalfin, won't really do that. It'll create a lot of total body on board, but can always be removed as a 2/2. Doesn't mean it's bad, but it snowballs differently.
It'll only really fit into even rogue or pirate rogue. The latter has never been good, but might be with a little support, at least in wild, and the former is actually potentially meta-defining as it's a great counter to paladin.