I will preface this post by saying that I am biased as I haven't done much PvP in the last year or so, so this is coming from a mostly PvE player, I have not used the spears in PvP yet and have also not gone out to look for them on islands.
I feel that the hunting spears are trying to do way too much and suffer for it. In my opinion, the ideas behind them are good. Great, even. But it feels as though they were initially two separate things that got merged.
My main issue is mostly in how they are handled as items. So, you can buy five hunting spears at each Hunter's Call location. And as well, they cost 250 for one singular spear. Yes, you buy them individually. There are 7 outposts and 8 seaposts, for a total of 15. So on the whole map you can buy 75 spears. It's not an incredibly small number, but the amount of sailing you would have to do is immense. In addition, they are world items (akin to the Trident of Dark tides) which means you can't carry more than one at a time and they cannot be stored in crates or barrels. Furthermore, another issue that pops up from their status as a world item is that you cannot get on a cannon while holding one. I suppose that issue could be mitigated with larger crews having a designated spear loader.
So, what do I propose for changes? I have a few ideas of potential changes that could be done.
1.) Make spears an inventory item with a very low inventory capacity.
I think this would be the simplest to do out of my ideas. It would make them easier to manage and to load as well, your ship doesn't have to be a pincushion and in theory might actually make them a little better for PvP because they would need to be put away not with the press of a single button, but you would need a storage crate or barrel to put them in. Slight edit for clarity: The "low inventory capacity" would be something akin to the bear traps.
2.) Instead of singular spears, make them a spear pack.
Another way of handling this could be making spear packs. They would retain their status as a world item and the tedium that comes along with it, but perhaps they could hold five spears at a time with the option of refilling them via singular spears that were thrown by other players. This would - in my opinion - make them more viable for combat away from the ship or wherever else you would be storing your spears.
3.) Split them up.
This way would potentially require the most effort both initially and over time, but as it stands it is the option that I would like to see the most. My idea is to make the hunting spears into a weapon - or at least a much more plentiful throwable. I personally don't think they ever needed the option to be loaded into cannons. If they would be turned into a weapon, they could perhaps deal damage on par with the flintlock, but have their damage doubled or maybe even tripled against wildlife and beastly foes, namely all wildlife, sharks, megalodons, krakens, ocean crawlers and sirens. This would give them a specific niche that no other weapon has which would be cool to see. Of course, I am not forgetting about the wedging into holes and stopping them from being repaired. That could be turned into a new very limited type of cannon ammunition, similar to scattershot.
Thank you for reading my post through!