That's a very interesting idea, Jadzia. It reminded me of FFXI fishing where you always had a chance to fish out a monster of some kind, depending on your fishing rod and water you are fishing in. Even though macroing in both FFXI and FFXIV (yes, I played both) is close to impossible due to fishing mechanics.
I think very simple fishing change would make it impossible to macro skills like fishing with simple non-tedious mini-games.
Check this video of Final Fantasy XIV fishing, for example:
http://www.youtube.com/watch?v=X9r0C_5XcRQ