My experience so far:
Wildhammer Clan (Twilight Highlands)
2.5/5 are collection quests. One kill X and one escort quest. The orc token quest drop for every character, you just have to IWT loot them with everyone.
Therazane (Deepholm)
3/6 are collection quests. Two kill X and one blow up Y mushrooms.
Tol'Barad
Different quests every day so it's hard to say exact numbers. Maybe a 70/30% split in collection/kill quests?
