Was out leveling up my Herbalism on my Hunter and run into one the attack areas and started killing the Scourge Invasion mobs for fun. Noticed they now give 10 Argent Dawn reps each for killing any of the Scourge mobs along with the Necrotic Runes which seem to drop more often now. This must have very recently changed. But they now give reps as well as they also now drop several quests also since I picked up like 4 quests. The Shadow of Doom which you summons I know gives 100 reps if killed and 30 Runes of loot which it did give before, just all the mobs now give reps it seems.
Since had the place all to my self for quite a while racked up almost 3K reps with the Argent Dawn alone their all by myself and a bunch of Necrotic Runes till I was out of ammo. So more places and mobs to get Argent Dawn reps from if your grinding it as well as Baron runs in Stratholme.