Automatically award a unique commendation for any activity completed solo. Could be a single, low score value commendation under Mastery to prevent excessive score farming in easy content but show that it still requires some mastery over the game to solo anything. Could also be a unique commendation category with varying commendations and values for different content, based on difficulty. Commendation score is the biggest blockade in Guardian Rank progress (for my part, at least), and an addition like this would mean antisocial cynics like me could progress, albeit slowly. Soloing dungeons, nightfalls and, lately, lost sectors does require more mastery of the game than doing these things with a full team and I find it strange it is not represented in the commendation system at all (it being a method of peer reviewing fellow guardians notwithstanding).