Especially since you can hyperspawn farm at least two of the factions – Fray Island in Northern Barrens gives Ratchet rep (up to revered), and one of the Ships in Venture Bay in Grizzly Hills gives Booty Bay rep (up to revered). [Spillover rep counts up to Exalted] There’s also the pirate base east of Caverns of Time in Tanaris for Gadgetzan rep, though the mobs there are quite a lot more spread out and have way more spawn locations.
Most, if not all mob spawns in both locations are able to be covered by ~5 people. Then it just turns into a game of whack-a-mole for all 5 players to keep mobs spawning at the maximum rate. You can still do it with one person, it just takes longer.
EDIT: Note: if you plan on eventually getting The Insane title, you’d have to nuke all your cartel reps to get to Bloodsail Honored (or revered/exalted, if you’re crazy enough. I stopped at revered. <_<). You might want to do that first before grinding Steamwheedle Cartel rep.