I think its more just the novelty effect of it being new. I mean think about it, we already know Destiny is greatly designed around Human Behavior Manipulation techniques. The game up to this point didn't really set the bar too high for itself as is, so when TTK came out and people began playing it, of course by simple comparison you're going to get blown away by it. It seems like a lot, but its really not. Those quests are just there to stretch out all the previous content, though for the "new players" who are just coming into Destiny with the Legendary Edition, they are going to be the ones who benefit the most from it. That is until come Year 3 when everything they are doing and all the gear they are collecting is once again reset and made obsolete.