if the large scale pve is implemented good and the fights are fun i hope they will implement it in the future.
So far a lot of mmos don't offer smart large scale stuff imo.
They all just have tougher mobs and 99999999999999999999999999999999 hp. That is the reason you need a lot of people.
I hope this won't be the case since so far the game is goin in a very none-creative direction and this would be the easy way out in designing such raids.
I really hope some developers start thinking about raids a bit in the future and get more creative since if not i prefer smaller groups by far. And its easier to create interesting content for them.

But if they keep catering to the solo-gamers there won't be a need for raid content since the more solo content you create the less "massive" the player-base gets.