I think to help close the gap between player's with significant experience and forge skill level differences their should be a third game mode: player MMR doesn't change regardless of the outcome of the match, they can play in teams, players can select a difficulty for a match; and the player character's stats are either buffed or nerfed depending the differences between the player's MMR and the match difficulty. Player's could even adjust the settings in this game mode to give raiders more lives or faster recharge times when they run out of them.
This way newer players can compensate for their lack of experience with the game and more experienced players don't have to safe guard them from making as many mistakes.
This game mode is more about helping less experienced players learn the game faster with the help of more experienced players and less about earning substantial match rewards.