I just started fishing and even on low level levequests, I noticed it would take a long time to even get 3 of what I needed, so I can't imagine what it will be like on higher level quests. I have gone up a couple of levels in the class just trying to get what I need, which kind of defeats the purpose of doing those quests for exp. I agree that miner and botanist quests were much quicker, but I also found myself getting overly frustrated when I had a 95% success rate and failed 3/4 attempts. In my own opinion, I feel fishing is a nice, relaxing way to pass the time in FFXIV. Good luck with completing your mission.