I was one of those people that would sit in Wintergrasp for an hour, eventually, I just said screw it and checked to see how expensive the fish used to make it were. Turns out, after the Kaluak Fishing Tournament, the fish are dirt cheap. My recommendation is to just buy the fish ;)

yes, but you'll spend a whole lot more time traveling between fishing nodes that you're net "fish feast/hour" will be a lot smaller than if you fished in WG, regardless of whether or not you've been attacked by a member of the opposite faction (if that becomes a problem, you can find a nice place under a bridge, on one of the supporting trusses of the bridge, where you can fish without being noticed). The only good thing about this method is the possibility of a turtle mount, which most people I think have given up on getting.

I do my WG fishing without getting PvP flagged by standing inside the northern border of Dragonblight and fishing into WG. This way I can fish peacefully for as long as I wish and the only combat I have is with a single elemental mob with a 10-12 minute respawn timer.

The fish ratio may not be equal but since I don't have to move around chasing pool respawns I can gather more fish in a comparable amount of time.