Pretty close to compiling for the first time in ages. It wont be anywhere near working though.

api/src/main/java/net/md_5/bungee/api/ProxyServer.java

@@ -6,6 +6,7 @@ import java.util.Collection;
 import java.util.logging.Logger;
 import lombok.Getter;
 import net.md_5.bungee.api.config.ConfigurationAdapter;
+import net.md_5.bungee.api.config.ServerInfo;
 import net.md_5.bungee.api.connection.ProxiedPlayer;
 import net.md_5.bungee.api.connection.Server;
 import net.md_5.bungee.api.plugin.Plugin;
@@ -74,13 +75,6 @@ public abstract class ProxyServer
      */
     public abstract Server getServer(String name);
 
-    /**
-     * Return all servers configured as proxy targets.
-     *
-     * @return all known target servers
-     */
-    public abstract Collection<Server> getServers();
-
     /**
      * Get the {@link PluginManager} associated with loading plugins and
      * dispatching events. It is recommended that implementations use the

api/src/main/java/net/md_5/bungee/api/config/ServerInfo.java

@@ -1,8 +1,13 @@
 package net.md_5.bungee.api.config;
 
 import java.net.InetSocketAddress;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
 import lombok.AllArgsConstructor;
 import lombok.Data;
+import lombok.Synchronized;
+import net.md_5.bungee.api.connection.ProxiedPlayer;
 
 /**
  * Class used to represent a server to connect to.
@@ -24,4 +29,41 @@ public class ServerInfo
      * Permission node required to access this server.
      */
     private String permission;
+    /**
+     * Players connected to a server defined by these properties.
+     */
+    private final Collection<ProxiedPlayer> players = new ArrayList<>();
+
+    /**
+     * Add a player to the internal set of this server.
+     *
+     * @param player the player to add
+     */
+    @Synchronized("players")
+    public void addPlayer(ProxiedPlayer player)
+    {
+        players.add(player);
+    }
+
+    /**
+     * Remove a player form the internal set of this server.
+     *
+     * @param player the player to remove
+     */
+    @Synchronized("players")
+    public void removePlayer(ProxiedPlayer player)
+    {
+        players.remove(player);
+    }
+
+    /**
+     * Get the set of all players on this server.
+     *
+     * @return an unmodifiable collection of all players on this server
+     */
+    @Synchronized("players")
+    public Collection<ProxiedPlayer> getPlayers()
+    {
+        return Collections.unmodifiableCollection(players);
+    }
 }

api/src/main/java/net/md_5/bungee/api/connection/ProxiedPlayer.java

@@ -1,8 +1,7 @@
 package net.md_5.bungee.api.connection;
 
-import lombok.Getter;
-import lombok.Setter;
 import net.md_5.bungee.api.CommandSender;
+import net.md_5.bungee.api.config.ServerInfo;
 
 /**
  * Represents a player who's connection is being connected to somewhere else,
@@ -31,9 +30,9 @@ public interface ProxiedPlayer extends Connection, CommandSender
      * closing the current one. Depending on the implementation, this method
      * might return before the user has been connected.
      *
-     * @param server the new server to connect to
+     * @param target the new server to connect to
      */
-    public void connect(Server server);
+    public void connect(ServerInfo target);
 
     /**
      * Gets the server this player is connected to.

api/src/main/java/net/md_5/bungee/api/event/ServerConnectEvent.java

@@ -4,8 +4,8 @@ import lombok.AllArgsConstructor;
 import lombok.Data;
 import lombok.EqualsAndHashCode;
 import lombok.ToString;
+import net.md_5.bungee.api.config.ServerInfo;
 import net.md_5.bungee.api.connection.ProxiedPlayer;
-import net.md_5.bungee.api.connection.Server;
 import net.md_5.bungee.api.plugin.Event;
 
 @Data
@@ -22,5 +22,5 @@ public class ServerConnectEvent extends Event
     /**
      * Server the player will be connected to.
      */
-    private Server target;
+    private ServerInfo target;
 }