I haven't been to Northrend yet, but I've been doing the Death Knight quest series on my 5-box RAF team and have been amazed at how boxer friendly the quests are. So far, I'm about 2/3 of the way through the series and at Level 60/61/61/61/61 (Yay for RAF and lols at granting levels within the team to pump up the leveling). The collection quests have either had a TON of items close together (the Saronite Dagger quest) or been 100% drops from easy mobs (there's one quest to get 20 crusader skulls, was worried about doing this five times, but the skulls are 100% drops from both Scarlet military and the hilarious level 30-40 citizens of the town).

I don't expect that Blizzard did anything for the sake of boxers, but certainly don't appear to be discourging boxing/leveling in groups. I suspect the high drop rate on many collection quests is deliberate - low drop rate collection quests are hated by all - whether boxing or not.