If you want to make fishing even better add mythical feathers to loot drop. Maybe one overnight? 2 or 3 if lucky event up to 10. 

Fishing gives Laila's Petals, which convert to Mythical Feathers.

Out of over 300 fairies I only had one T4 and 2 T3 so technically and practically you won't get any mystical feather this way.

Not sure what you're talking about, if I exchange 10 fairies at least 1 of them can be exchanged for a mythical feather. They're also not hard to obtain, do your dailies and weekly. Fishing should be more rewarding for people that aren't AFK fishing though. AFK fishing gives what? 20mil overnight? That's like 10 minutes of effort or 8hrs of electricity. I'm not sure why people even AFK fish anymore?

I don't think mythical feathers should be a direct reward for gathering or fishing or combat. It should be a separate process entirely. The easier they make them, the less value they have in the end. It would be like if they made infinite potions 3x easier, everyone would have one and it would defeat the purpose of its novelty. With that said, I will continue to be against RNG and more about progressing in a game, but this is BDO which is sadly always going to be RNG for everything =/