I am a long time player of Neverwinter Nights 1 (NWN1). I think that game is a loose end that was left by Bioware.
All MMO developers of today have been blinded but what is already there. Noone is looking what can be done differently.
I think a similar game system as NWN in a more modern graphics MMO can actually become a big hit.
One has to rethink what MMO stands for however and make a high-risk niched harcore game for D&D vetarans...
Now...looking at NWN persistent world servers playing...what can be "stolen". Well, pretty much I think.
First the game itself. Let's just say Bioware made a great job and any developer just looking at this could probably make a lot from it.
Even though the game engine is utterly old i think it just needs some small changes to be able to be used for a modern game.
The gameplay system and GUI...its also something you can almost use straight out.
I think the gameplay system and combat system in this game is the closest to D&D/pathfinder you can get without going straight out turn based.
It is a "middle way" between pure action (fps-style) and turn based that works very well I think. Most MMO games are somewhere in the middle of this system and the pure action...with even most new MMO's actually going full action.
There is a tendency of newer games to move more towards action...so actually looking back at NWN is a good thing here I think.
Lets now look at the massively aspect. I think one should not be blinded by the effect of many players. I have played on NWN worlds with just a few playes on that felt a lot more alive than a WoW server with probably thousands on...
So..its not just about throwing thousands of players on one server. I think it is about "forcing" players to work together. Yeah...I know...this is more co-op....but this is an important part of what a roleplaying game is i think.
In this case thinking MMO is wrong. Thinking co-op is right. You don't want to have the normal MMO where everyone is running around soloing...
We have a big world full of real humans....so lets make use of it and actually use thoose humans...
Another thing you see in most MMO's is the over the top on "fantasy". I mean this is beyond fantasy. Every thing you see looks so unreal. That sucks! Go back to what D&D stands for!
I could probably go on but I'll spare you for now.
If anyone wonders what the hell I'm talking about and what is this game I'm talking about...feel free to ask...
(However...the only way to understand Neverwinter Nights, how it works and how it is different from all MMO's is to play it.)