I am no expert in game programming but I wonder if it is possible to include some kind of growth system into the game eventually? Where fish weights fluctuate with natural growth and times of the year where they may be a little lighter than other times and vice versa. Also have up and coming fish that grow into Trophy/Boss catches over time. If this is remotely possible I guess you would need to add some sort of seasonal/time element as well which I think would be a good idea anyway for the game even without a growth system. I liked the clock/time aspect in Euro Fishing where you could experience dusk til dawn and the changes in fish activity in the time gaps in between. Also as Euro Fishing had, bring back the wind direction!