FTA:

The collection will feature the Japanese and western versions of Raiden spin-offs Raiden Fighters, Raiden Fighters 2: Operation Hell Dive, and Raiden Fighters Jet, which were originally released in 1996, 1997, and 1998, respectively, as well as remixed music.

Actual game line up, release dates, and targeted platforms have not been announced yet. In fact, other than the information stating that this release is actively being worked on, there's no other info at all.

I will be especially interested in all the ways this upcoming release will differ from the Raiden Legacy release that already exists, which features the original Raiden, Raiden Fighters 1, 2, and 3.