Well according to wikipedia its supposed to be and I don't see why it wouldn't be. I haven't played legendia so I didn't know it was a 1 player only game that would suck if they ever did that with any future games I got friends I love playing the tales games with.
I really enjoyed legendia but I have never had a chance to play the tales series through with a friend or relative. It does sound like a lot of fun but I am sure I would always argue over who gets to control the characters when not in the battle system lol.