I imagine it will be something similar to Minecraft or the original FFXI fishing; you cast your line, wait for a hit, then grab your fish.

Fishing was heavily botted in FFXI because you could sell some fish for decent vendor gil, and then there was the moat carps.

As long as they keep vendor purchasing prices extremely low (near 0), people will only sell them on the market. So, even if RMT wanted to bot fish like crazy, they'd could only do good things for everyone by supplying cheap fish for everyone to freely purchase or not, as opposed to artificially inflating the currency and reducing the purchasing power of other players.

As to the specific topic at hand, I really just want FFXIV fishing to be like zelda fishing. I'd wait another year for that if it was necessary... but I can see why there's a place for casual fishing... and though I will always prefer more awesome fishing, Yoshi seems to think more people want it to be casual... and I can respect that.