Disheartened does the same as in SD2, with an increase to the Cohesion damage suffered, except Suppression and Cohesion function differently. Units do not get suppressed / forced to flee like in SD2 when the bar fills up. They do lose accuracy and reload speed, as well as movement speed (this is a significant change). Sometimes units in WarNo will get Stunned or Routed, with Routed being tied to Cohesion damage, but being a fairly uncommon occurrence. Units will also rank up in experience levels when they inflict damage or kill other units. I don't know the exact math, but the XP gained is based off the difference in value. So KDA units rank up fast if they survive, since they're all dirt cheap. And it's not that hard for them to survive at 15 HP base. It's a bit like the 16th Luftwaffe, they're crap in a vacuum, but if they're supported by a solid leader network, they're actually good, and excellent considering their price.