I came to this forum recently, I have a lot of suggestions but some of them aren't meant for this game.
While thinking which one would I suggest, I stumbled upon this idea:
"Avalon" The Flying Fortress
So imagine that this is a dungeon which can be entered if found someplace in the world, It travels around the world, floating freely in the sky, and can be found only using such items as: Magical Exposing Compass or other stuff like that.
Avalon dungeon would be different for every 7 levels.
When using an item which can be obtained by completing a certain quest, you can get inside the Avalon, where you will find a door for every 7 levels and only the matching level stage door will be unlocked.
Every door is unlocked by passing 7 levels but when the player reaches the next stage(next 7 levels) previous door will be locked e.g. Levels 7-14; 14-21; 21-28 and so on. Levels 1, 2, 3, 4, 5, 6 can not access dungeon doors.
When entering the dungeon there shall be 3 mini bosses and the main boss at the end of the dungeon. It can be entered with a team (party) maximum of 6 people and minimum of 1 person.
Only the players matching dungeon door level can be in the same team e.g. LVL 7-14 players can not be in the same team as LVL 21-28 players. This rule is needed in order to prevent/reduce trading real cash in game from player to player.
For this idea to become true there needs to be an addition to be able to see the sky and rotate the screen (The type of things done in first person games) or make a separate entrance for Avalon which can be unlocked with a key gained in a certain quest (I suggest this quest name: Entrance To The Skies) but for it to still be a flying fortress, on the loading screen add an Image of Avalon.
You can freely use my ideas or any fragment of the idea for the game development.
Please comment if this idea is good or not. Any feedback is appreciated!