Ok, well I recently found a fishing spot, not sure if it's been posted, did a search and didn't find anything, but it allows you to fish in WG waters without getting pvp flagged.
The spot is on the waterfall in Icemist Village, to the very west of Dragonblight. Fly up to the top by the rocks get as close to wintergrasp as possible without zoning in, and your line should reach the water. Again, sorry if its a repost.