In terms of its effects it is quite different from the ticket system. I was never sure if the ticket counter included those on the battlefield or not but you knew when you were running out and the affect wasn't immediate. You lost the ability to respawn but those still fighting could continue and did sometimes run the clock out before they got all killed.
The morale system if I am interpretation is correct is an abrupt collapse of you force. When it hits zero everyone surrenders regardless of how well they are doing. All the player knows is that his side is within 25% of failure. If I am interpreting things said correctly there is no change to spawning. Those killed can respawn right up to time of surrender.
Lightfoot