One major system change compared to Valkyria Chronicles 2 is all characters can be changed freely between the five soldier types. Some characters, however, will have strengths and weaknesses. After battle, all troops in the fight receive experience points.
Valkyria Chronicles 3 also changes the battle potential system a bit by introducing a visual grid called the "master table" where you can direct characters sort of like Final Fantasy X’s sphere board.
Sega has Valkyria Chronicles 3 slated for January 27, 2011 in Japan. Currently, the PSP game has not been announced for North America.
Update: Sega released screenshots of the two-mission demo. Clear it and you’ll be able to import the save file into the retail game to obtain a limited weapon. The Valkyria Chronicles 3 demo requires 160MB of storage space on a Memory Stick.