A MMORPG IDEA

A few years ago I played a game called Dungeon Runners. It was a free to play game similar in look to other 3D games (such as Everquest, WoW, etc.) but featured a different style of world. In DR you began at a starting town that served as a safe zone free from monsters and which contained everything one needed while away from dungeons (other players to interact with, a bank, merchants, and quest givers). I thought it was a fun game to play in the short time it lasted (from May 24, 2007 til Jan. 1, 2010). I copied maps of the many dungeons to help me in my explorations and played it eagerly for a good while. When I discovered it had gone kaput I was gravely disappointed and I will always miss being able to log in to this virtual world.
At any rate I had an idea for a mmorpg much like Dungeon Runners. See the illustration below:

This starting 'HUB' would be enough to get players started in their exploits in the game and other hubs could be added as needed, accessed perhaps via a portal system from the starting town (which would take one to some other town with paths leading to higher level dungeons (Dungeon Runners had a system like this in fact too).
Another note about the dungeons of my game is that they would be random each time you visited them. Dungeon Runners had this feature too, but in only slight ways. In my game the dungeons could be extremely different each time you entered, with different bosses and paths to take. Overall it would resemble Dungeon Runners a good bit, but would be at least as enjoyable and hopefully even more so.
An example of the differences in my dungeons might be that the number of paths to explore/and therefore the number of bosses to defeat/would be different each time visited. Also the type of terrain or environment might change from visit to visit or perhaps even path to path inside the dungeon. some paths might be underwater-some in very cold or very hot areas. Some paths might lead on to others or come to a dead end. Or some might be inhabited by poisonous plants, etc. There could be dozens of boss types to randomly choose from that the players would have to fight. Some bosses would be greater than others and there could even be like a hierarchy system for them (like some might be like princes, some like queens, some like kings, etc. You wouldn't always get a king to fight, and if you did it would be a special run & drop much better treasure, although the fight would be much tougher)
I think it would be cool to try and design a game like this & I'll be looking in to ways in which I could try and make it happen.
http://en.wikipedia.org/wiki/Dungeon_Runners