For the longest while we've all been under the impression that every single Operation with its different iterations of difficulty would survive into Fallen Empire. The operations blog served as a confirmation to this.
Today, however, news has emerged that the Nightmare Iterations of both Eternity Vault and Karagga's Palace are being outright removed when the expansion launches. With them go the chance to earn the "Infernal" and "Unyielding" titles and every Nightmare Achievement, which, unlike the Makeb Weekly Achievements, are simply being moved to an "archived" section of Achievements and not permanently removed.
I can see why they've done this. Neither Nightmare EV and KP are anywhere near as challenging compared to their Hard Mode iterations as their later NiM cousins, so keeping these in the game would provide for a very simple manner of groups gearing themselves using Nightmare-Grade Gear week after week. To be fair, groups will be able to do this anyway using the "Highlighted Hard Modes", but better to have all Operations of this type present similar challenges rather than have two weak points.
I like to view this as a sign of how much Nightmare Modes have evolved since their introduction. NiM EV and KP were all about the "challenge" and never about the gear since it dropped the same as Hard Mode; Rakata. From NiM EC onwards, the challenge, whilst this was still a presiding factor, was ramped up significantly and NiM became its own considerable tier of progression with its own gear.
On the other hand, I am slightly disappointed that they aren't in some way tweaking these Operations at that difficulty and keeping them in, especially with the fact that they've been left behind ever since NiM EC was introduced. Eternity Vault is still one of the best Operations they have done, so it will be a shame to see it reduced to just Hard and Story Modes.
As far as I'm concerned, this change is thus a double-edged sword. I like that they are in some way managing this vast discrepancy between challenge between the various Nightmare Modes, but it is still disappointing that there wasn't another path beyond outright removal, or at least not that we can see to have been considered.