...this game needs to be made...custom made lakes...fun...!
Or procedurally generated.
Could you imagine having a tournament with generated lakes??!!! It would be so sweet. No one would have previous knowledge of the "secret fishing holes". You would have maybe a two day window to scout the lake to find these spots followed by a three or four day tournament. Use the existing art from TGC for shoreline/themes.
Keep the camera above water because in real life, you usually (except for a few) can only rely on fish finders and experience to find fishing spots. Have a window that shows the action of your lure/bait or something to indicate you are trolling or retrieving at a proper speed. Like I said, I think the Atlus game on XBOX did it right, it just never developed multiplayer/online portions enough. I would think that HB could adapt much of the technology from TGC to fit the bill.
And they could, as previously mentioned, sell a hybrid called something like "Weekend Getaway" where you can play The Golf Club and The Fishing Club together. Fish the lakes on course. A group of coworkers and I used to have a "Skins and Fins" weekend involving both golf and fishing.
I would LOVE to see TGC coding adapted to TFC (The Fishing Club). I would also volunteer to any fan input group/forum.