It was obvious it had to be done like this back then because that was the only content and the levelling was different. But what about now? As a new player joining the game. Do you need to do VoG/Crota? Nop, worthless!
That's one of the complaints I have about this game, the way the story progresses. I mean like when you have the vanilla quest lines, they decide to randomly jam TDB's storyline as well as HoW. A new player would be like "Why aren't Crota's forces going against the House of Wolves?" At the very least, they could've included the raids in those quest lines, then make it so you have to beat one to get to the other.
This is getting a bit more complicated because if you tie in raids to the quest line then you are forcing the player to progress trough the game.
FF ARR/Heavensward is a great example of mmorpgs evolving and offering the player multiple choices for progression. RifleAvenger can back me up on this one, or anyone that played FF, if you want to raid casual or hardcore thats fine but if you don't want to raid you should still have means to reach max level and stuff. In FF you could do every piece of endgame content by not doing any raids. There where sooo many options available to the player. This boils down to how the game is developed, because in a heavy orientated raiding game A LOT of the player base will leave when there is nothing to do but raids.