I do feel like the concern of over-reliance on boards is because naval is underpowered since it's.. really easy to undo damage done if you're not boarded. If you're hyper aware of boarders, they're invincible unless you kill players on top deck, which isn't going to be the easiest thing to do unless players make themselves easily vulnerable. They can be shot down, but they just have to go under the deck and eat food till they can sponge another long range hit. They can be killed by cannons, but again, they just have to go under the deck and eat food till they can sponge anymore damage, unless you get the lucky (for you, unlucky for them) one-ball.
No one likes a long fight, and boarding the "reasonable" way is the only way to cut a fight short of constant naval defense. It's why people complain about crew size differences, but that's besides the point. As much as I'd want there to be unique boarding ideas, there's nothing that keeps the current balance we have and makes it feel fair. Boarding axes wouldn't fix it, ziplines would be far too janky, hiding mermaids would be absurd for even the most aware of players.
I do think we should open a proper discussion with the developers to make naval fights as swift as TDMs, without needing to have a massive skill difference against a crew to sink them quickly.