(Disclaimer; I don't know if you can do this now, but when I last tried you couldn't)
Since I am such a fish fanatic and I believe the primary reason that fishing was 'fixed', I have taken it upon my self to try and slide in something a bit more engaging than sitting in your boat cranking it to a extra sexy tuna.
A very old server I played on had fishing and it was a suitable job, being able to give you sufficient money for hard work. You were able to swim up to any fish (not turtle) and pick it up with windows key, enabling people to pick and choose the fish that they want and expend the effort to pick the most expensive fish and thus making more profit.
My suggestion is pretty basic:
Make people able to pick up all fish with windows keys without having to kill them beforehand.
Now I have no bloody clue if this is possible anymore but I don't know, it'd be more fun.
Little bit extra;
Make fishing a lil bit worth while, or easier. Like make the storage space on boats more idk.