"Raiding" in the traditional sense is never coming to GW2, I've come to terms with that fact a long time ago. But why would something similar not be feasible? For a game that lauds that I can "play the game the way I want to" I sure can't play the game the way I want to. With the new rewards system they're announcing, which is basically rewarding you for whatever you do, why couldn't they release something else though? Just have it reward the same rewards. Nothing more, nothing less. Large scale PvE content (or whatever else they come up with) doesn't become "the" endgame. It becomes "an" endgame. People who don't do it can progress at exactly the same pace as those that do it, perhaps even quicker if they're doing many things. This helps GW2 avoid a lot of the issues that games with traditional raiding have.
Edit: For further clarity, let me give you point comparisons.
What I'd like to see:
Lore-based, large scale GROUP content (> 5 people)
Fun and interesting encounters
Sense of exploration
A sense of progression
What I don't want to ever see:
"Tiers" of gear
"Raid"-only gear, mounts, vanity items, etc.
Automatic group formation
They are never going to add the latter. That is a good thing. No complaints here. Whoopee hooray! The former, however, is not currently in the game (DEs don't make the cut, please don't bring up that argument). So why can't they add that in? What negatives am I missing here? Tie the progression into the rewards system and it becomes completely optional. Encounters don't drop gear, only these tokens. Use these tokens to buy gear if you want, or just pretty vanity items (I have my eye on you, you mysterious cat tonic). Or don't buy anything at all. Just do the encounters for the sake of enjoying the encounters.