Back in the first iteration I tested of the crafting systems, fish were part of Provisioning. They were ingredients. You could catch some fish and take them to a cooking fire and fry them.

That overall crafting system was not fairly intuitive for other non-fish related reasons. This new system is better in every single way...except you took the fish away

I can't be alone in wanting them back. Currently fish serve no purpose except for grinding out achievements. I mean sure it's a time sink, but that's it.

I know a lot of recipe variants exist. Perhaps fish could be made into additives for blue or purple recipes. There aren't very many purple recipes and they seem to drop for only 2 levels in the entire game. Expanding the amount of purples could give you the opportunity to integrate fish into the system.

Fish would immediately become a commodity for provisioners. It would give Fishing a purpose aside from achievement grinding.

The only downside I can see is that farmer bots might camp all the fishing hole spawns and overfish them until they're gone. But they do that already with nodes and people are still able to find raw materials without buying them from a farming bot.