First off I want to start by saying overall I enjoy fishing in GW2 and think the first stab at getting it into the game was a great effort and the system is set up for success in the long run. However, as the title suggests, there are some pain points which detract from the fun. They are as follows in my personal opinion.
Fishing stacks should remain in place when you are forced off a map due to low population. The players should not be punished because the map closes due to low population, this is a terrible mechanic. At no point in any game should a player be punished for something that is entirely out of their control. Why this is even a thing is beyond me.
Having the entire fishing pool open to be caught at Dusk/Dawn needs to go. It is simply silly and bad design to allow players a 5 minute window once every hour or more to catch a certain fish and then make every day/night specific fish and non time specific fish available to be caught as well. At most it should be limited to Dusk/Dawn fish and non time specific fish in that catch window.
The drop rates are still terrible and there seems to be a hidden mechanic that reduces the chances of catching fish you have not caught yet. Many times now I have noticed this trend, you are left with a single Exotic or Ascended fish to catch in an area but you end up catching 10+ legendary fish before the one you need. There shouldn't be any form of artificial time gating, and if there isn't the drop rates need some major adjustments across the board, there is no reason someone should be consistently catching 10+ legendary fish before ever catching a single exotic/ascended. If this happened once in a blue moon, sure it is probably just RNG, but the number of times this has happened to me alone suggests this is more than just RNG being RNG.
Achievement points should be given for at least the first completion of Avid Fisher in each zone. Almost every other repeatable achievement in game gives you points for the first completion, if not more. While some may say points were already given for the first completion, yes technically they were, however, since the normal zone complete and the avid zone complete are both required to complete Cod Swimming Amongst Mere Minnows, these really are two separate achievements at that point.
That is all. Thanks.