My suggestion is to change the way of how fishing rods are used. Currently, when you use fishing rod it shows a little loading symbol and a majority of times three dots. With the current fishing rod system a huge amount of times you do get nothing. Although, in a current way it is quite realistic when being in the game many players go to catch many pokemon to find the ideal ability and nature ext.. The way this could be changed is by implementing a bar with a point moving from left to right and an area where you need to press space in order to catch (start a battle) with the pokemon.
This change would make catching more like a minigame and it would make fishing a less time consuming in-game activity. Understandably, this can create a problem with how better types of rods will be different from the weaker ones. This could be compensated by having pokemon only up to a certain level for each rod (for example the maximal level of 10 for the old rod), as well limiting the uses of rods to a specific area and/or pokemon.
Of course, I am not a game developer, just a random teenager, so I cannot tell if it can be done. I am sorry if it is completely useless, it is just that when you are trying to catch a water pokemon for quite a while before having surf (or even to get surf), it does get quite disappointing when you cannot even catch Magikarp.