The new game was originally in development as a brand-new game and franchise called Hardware: Shipbreakers. Blackbird Interactive, founded by many of the same team who worked on Homeworld and Homeworld 2 at Relic Entertainment. In 2012 Gearbox acquired the Homeworld IP and began work on HD, remastered versions of the games which launched to critical acclaim earlier this year. Thay also agreed to partner with Blackbird to release Shipbreakers, granting them permission to move the game into the Homeworld universe.
The original theory was that the game would be thoroughly reworked into a prequel to the original Homeworld, set on the desert planet of Kharak and depicting the feuding Kiith (clans) in their run-up to finding the crashed starship that would set them on the course to building the Mothership and seeking their true origins. However, the video from the developers' conference suggests that the game may instead be a prequel to Homeworld 2, taking place between the two games, and depicting a much larger-scaled ground conflict over a different planet. The presence of ruined ships from the first game (which wouldn't make sense in the lore for a true prequel) seems to lend weight to that theory.
The video also suggests that the game may have grown into a larger affair, maybe more akin to Supreme Commander with the ability to zoom all the way into low orbit and fight across truly vast stretches of territory.
The video focuses on how the developers have used the Unity Engine to render cut-scenes, which would seem to confirm that the game will now feature a substantial single-player campaign running alongside the already-confirmed multiplayer mode.
Nothing more about the game, such as a prospective release date, has been revealed so far.