The "Man Up Rule" removes stalemates in Execution/Warzone if one team has more players alive than the other.
Epic's addition of the "man up rule" ruins the impetus of the team in the lead to hunt down the weaker one.
This rule forces both teams to basically play super conservatively and to create "grenade fortresses" and attempt to bore the other team into striking first. When the first player is lost the man up team has no reason to even attack the man-down team. They can just sit in their grenade fortresses and time out the game for the win.
This turn of events was likely put into place to degenerate Execution/Warzone and force all elimination players to play Team Death Match.
I propose Epic fix this problem immediately before they kill off Gears's 2 oldest running gametypes.