The official announcement was made as of this past Friday from the Neverwinter Facebook page; their server upgrade goes live tomorrow, Tuesday October 8, 2013. This statement was coupled with the warning to keep this in mind regarding player auctions, Celestial coins, etc. Imaginably a cover on their part for the impacts most likely to affect the players in a way that could stir up any potentially negative reactions. The official news posting found here, has been updated with the official date and time of the 'go-live' on this move.
Whether the Perfect World/Cryptic team had planned this merger all along as a fail-safe to player- interest decline is unclear; typically in the past MMO games that have seen this type of merger take place have been directly impacted by server population drops. Regardless of the reasoning behind this original intent, unlike the other MMO's that have commit to this type of merger after going live, the team behind Neverwinter has been dangling this promised merger like a carrot on a string since going live. This alone presents an entirely different reaction by the community to this announcement than has been observed from any other MMO's having seen this same strategic move.
One could speculate that this was a fail-safe that was put on hold until an average number of regularly live players could be determined for handling purposes, it could be even as simple as a coding issue that was unable to see proper handling until now. Whatever the actual reasoning behind this server merge, due to their announcing plans of as much from as early on as during the Beta of this MMO; it comes as little surprise that the merger is being welcomed by more of the players than not. Rather than feeling their game is being slowly dissolved in this move, a message of success and measuring up to promised intent is conveyed and definitely felt by their player-community.
Hopes run high that this fulfillment of their intended goal stands as a beacon of hope for the many aspirations the players have of this game; while other MMO's struggle to keep player populations adequate for the entertainments they offer, the team behind Neverwinter definitely had a strategy going in to prevent any fears of as much from residing in their community's mind for long.