First, I would suggest reviewing the developer diary on the changes to Delvings
here for an outline of the changes being made to Delvings.
Second, I am not going to bury the lede. What you are seeing regarding the new "BiS" necklace is only one of the avenues by which the item can be acquired. When we introduced Delvings we were pretty clear that they would be an alternate way to get raid level gear. We are sticking to that direction. Delvings are
a way to get the new "BiS" necklace, but not the only way. The necklace will drop, unsurprisingly, in the raid - once it becomes active and players reach the correct tier for the item to drop.
In addition to this, the lumps of silver are available in more potential locations, which should make them easier to acquire. The reason that the Delving system was chosen for
a way to acquire the new "BiS" necklace was to provide a reason to hang on to those Sarch Vorn necklaces - and not completely remove their value with the onset of U35.
Third, because we know that the acquisition channels to get the new "BiS" necklace may not appear to everyone, we already have a plan slated to make the item more readily available to those who have not been fortunate enough to acquire the item through more traditional means. This solution appears a little later in the year, when the item will still have relevance.
We will continue to do our best to provide manifold avenues for item acquisition, and while we may not always come out and provide drop rates, or indicate where the items are going to be found, it is not because we are trying to obfuscate the information. Rather, it is that we still think that there are some players who like to discover and learn things on their own.
The TL;DR here is: more than one way to get the new BiS Necklace and the Delving avenue might be most time intensive way to get the item. While this may not be a desirable route to acquire for every individual player, it remains an
option to all players.