It feels like an improvement to the old system where rounds suddenly ended without warning when a team broke.
That being said the functionality of the mode effectively changes the rules of the game in that how you die no longer matters. This goes for the attacker and the defender. It's as if the game suddenly says "You know those rules you were going by, well they don't matter any more to the team that breaks." Yes there is an urgency put into place for the defender to not die and the attacker to move quickly but, especially for the attacker, it's like the old rules are dissolves. It also effectively dissolves the incentives to play in the style the main game encourages.
Now I think the team morale system is barking up the wrong tree in the first place and that all the incentive should be on the individual player and not by punishing the team score. But at the same time it doesn't make a whole heckuva lot of sense the way the last stand functions as a competitive and realistic game. A "final push" team has effectively been relieved of the old rules that were supposed to hold the team together.
I thought I'd point this out since nobody has yet.