Yeah, this is definitely the last of the second batch, and he while he doesn't rule out a third batch it doesn't sound like we can count on it happening any time soon.
I'll go over the interview in more detail later, but here are some tidbits:
-Unlike most of the other games, they were actually able to locate the old AM1 source code for Thunder Blade, but the code they found was an "in-between" revision that didn't neatly conform to any one release version, which meant they had to spend a lot of time cross-checking with various versions of the board to ascertain what was what
-The "Extra BGM" tracks included with 3D Thunder Blade are similar but not identical to the ones features on the Galaxy Force 2/Thunder Blade OST CD; the arrangements are a little more elaborate, and they had to go in and fix the source data so that the songs would loop properly.
-Some of the "new" enemies in the special mode are based on unused enemy graphics that were found in the ROM
-For the new stage, they received assistance from a freelancer who once worked for ZOOM and did pixel art for games like Phalanx X68000, and now does illustrations for the magazine Shooting Gameside. (Here's his Twitter:
https://twitter.com/highmafuyuno )
-Okunari likens the original final stage to the Death Star from Episode 4, and the new final stage to the Death Star from Episode 6