Its been a number of years since I've played, but IIRC TSL seems to loosely imply that Revan and Canderous had some sort of understanding before Revan left for the Unknown Regions (Kreia prods Canderous but he replies something to the effect that it is between him and Revan). I got the feeling that the understanding was essentially that Canderous would revive the Mandalorians to fight on behalf of the Republic (or the galactic status quo) against the True Sith or whatever Revan stirred up that threatened the galaxy. In doing so, the Mandalorians would redeem themselves in the eyes of the future Republic for the horrors they wrought in the Mandalorian Wars.
Kreia mentions something to the effect that the Mandalorians are a dying civilization being organized by Canderous for "one last hurrah."
Without knowing exactly what direction TOR or a potential K3 will go with it, I will assume that somewhere along the line a (mostly) unified Mandalorian people will put forth a heroic stand against a Dark Side threat that will eventually see the end of their civilization -- the remnants becoming the nomadic, mercenary people of the late Old Republic.