Wasn't meant to be
The GameCube saw release of two Baten Kaitos titles, both of which appeared to be a decent hit with RPG fans. Those titles will soon have a second chance to find another round of success with Baten Kaitos I & II HD Remaster coming to Switch. Unfortunately, what we never got back in the day was a third Baten Kaitos title.
With Baten Kaitos: Eternal Wings and the Lost Ocean and Baten Kaitos Origins being modest hits, you might have thought that a third entry would be somewhat of a lock. According to Yasuyuki Honne, Monolith Soft dev who directed both Baten Kaitos titles, there were indeed plans to continue the franchise, but they never materialized.
Honne reveals that work on Baten Kaitos III did begin, and it had a target of next-gen systems at the time, which might have included Wii. Unfortunately for the devs, Bandai Namco went through some restructuring and budget shifts, and co-developer tri-Crescendo was also facing financial issues at the same time. This led to any work on Baten Kaitos III being halted, and plans for a DS Baten Kaitos title to be scrapped down the line as well.