You can now define a maximum number of players for a roundtype if you so desire, but no round type currently does this.

Server owners can now futz around with the minimum / maximum number of players for roundtypes via game_options.txt

code/controllers/configuration.dm

@@ -100,6 +100,8 @@
 	var/list/modes = list()				// allowed modes
 	var/list/votable_modes = list()		// votable modes
 	var/list/probabilities = list()		// relative probability of each mode
+	var/list/min_pop = list()			// overrides for acceptible player counts in a mode
+	var/list/max_pop = list()
 
 	var/humans_need_surnames = 0
 	var/allow_ai = 0					// allow ai job
@@ -536,6 +538,34 @@
 					config.midround_antag_time_check = text2num(value)
 				if("midround_antag_life_check")
 					config.midround_antag_life_check = text2num(value)
+				if("min_pop")
+					var/pop_pos = findtext(value, " ")
+					var/mode_name = null
+					var/mode_value = null
+
+					if(pop_pos)
+						mode_name = lowertext(copytext(value, 1, pop_pos))
+						mode_value = copytext(value, pop_pos + 1)
+						if(mode_name in config.modes)
+							config.min_pop[mode_name] = text2num(mode_value)
+						else
+							diary << "Unknown minimum population configuration definition: [mode_name]."
+					else
+						diary << "Incorrect minimum population configuration definition: [mode_name]  [mode_value]."
+				if("max_pop")
+					var/pop_pos = findtext(value, " ")
+					var/mode_name = null
+					var/mode_value = null
+
+					if(pop_pos)
+						mode_name = lowertext(copytext(value, 1, pop_pos))
+						mode_value = copytext(value, pop_pos + 1)
+						if(mode_name in config.modes)
+							config.max_pop[mode_name] = text2num(mode_value)
+						else
+							diary << "Unknown maximum population configuration definition: [mode_name]."
+					else
+						diary << "Incorrect maximum population configuration definition: [mode_name]  [mode_value]."
 				if("shuttle_refuel_delay")
 					config.shuttle_refuel_delay     = text2num(value)
 				if("show_game_type_odds")
@@ -774,6 +804,10 @@
 		if(probabilities[M.config_tag]<=0)
 			qdel(M)
 			continue
+		if(min_pop[M.config_tag])
+			M.required_players = min_pop[M.config_tag]
+		if(max_pop[M.config_tag])
+			M.maximum_players = max_pop[M.config_tag]
 		if(M.can_start())
 			runnable_modes[M] = probabilities[M.config_tag]
 			//world << "DEBUG: runnable_mode\[[runnable_modes.len]\] = [M.config_tag]"
@@ -789,7 +823,13 @@
 		if(probabilities[M.config_tag]<=0)
 			qdel(M)
 			continue
+		if(min_pop[M.config_tag])
+			M.required_players = min_pop[M.config_tag]
+		if(max_pop[M.config_tag])
+			M.maximum_players = max_pop[M.config_tag]
 		if(M.required_players <= crew)
+			if(M.maximum_players >= 0 && M.maximum_players < crew)
+				continue
 			runnable_modes[M] = probabilities[M.config_tag]
 	return runnable_modes
 

code/game/gamemodes/game_mode.dm

@@ -25,6 +25,7 @@
 	var/list/restricted_jobs = list()	// Jobs it doesn't make sense to be.  I.E chaplain or AI cultist
 	var/list/protected_jobs = list()	// Jobs that can't be traitors because
 	var/required_players = 0
+	var/maximum_players = -1 // -1 is no maximum, positive numbers limit the selection of a mode on overstaffed stations
 	var/required_enemies = 0
 	var/recommended_enemies = 0
 	var/antag_flag = null //preferences flag such as BE_WIZARD that need to be turned on for players to be antag
@@ -56,7 +57,7 @@
 		if((player.client)&&(player.ready))
 			playerC++
 	if(!Debug2)
-		if(playerC < required_players)
+		if(playerC < required_players || (maximum_players >= 0 && playerC > maximum_players))
 			return 0
 	antag_candidates = get_players_for_role(antag_flag)
 	if(!Debug2)

config/game_options.txt

@@ -141,6 +141,62 @@ MIDROUND_ANTAG BLOB
 #MIDROUND_ANTAG  RAGINMAGES
 #MIDROUND_ANTAG  MONKEY
 
+## Uncomment for overrides of the minimum / maximum number of players in a round type. 
+## If you set any of these occasionally check to see if you still need them as the modes
+## will still be actively rebalanced around the SUGGESTED populations, not your overrides.
+## Notes: For maximum number of players a value of -1 means no maximum. Setting minimums to 
+## VERY low numbers (< 5) can lead to errors if the roundtypes were not designed for that.
+
+#MIN_POP TRAITOR 0
+#MAX_POP TRAITOR -1
+
+#MIN_POP TRAITORCHAN 15
+#MAX_POP TRAITORCHAN -1
+
+#MIN_POP DOUBLE_AGENTS 25
+#MAX_POP DOUBLE_AGENTS -1
+
+#MIN_POP NUCLEAR 0
+#MAX_POP NUCLEAR -1
+
+#MIN_POP REVOLUTION 20
+#MAX_POP REVOLUTION -1
+
+#MIN_POP GANG 20
+#MAX_POP GANG -1
+
+#MIN_POP CULT 24
+#MAX_POP CULT -1
+
+#MIN_POP CLOCKWORK_CULT 24
+#MAX_POP CLOCKWORK_CULT -1
+
+#MIN_POP CHANGELING 15
+#MAX_POP CHANGELING -1
+
+#MIN_POP WIZARD 20
+#MAX_POP WIZARD -1
+
+#MIN_POP BLOB 25
+#MAX_POP BLOB -1
+
+#MIN_POP MONKEY 20
+#MAX_POP MONKEY -1
+
+#MIN_POP METEOR 0
+#MAX_POP METEOR -1
+
+#MIN_POP DEVIL 0
+#MAX_POP DEVIL -1
+
+#MIN_POP DEVIL_AGENTS 25
+#MAX_POP DEVIL_AGENTS -1
+
+## Setting at least one mode to be playable at 0/1 players is required.
+#MIN_POP EXTENDED 0
+#MAX_POP EXTENDED -1
+
+
 
 ## The amount of time it takes for the emergency shuttle to be called, from round start.
 SHUTTLE_REFUEL_DELAY 12000