. I have reverted to a design that creates a world setup like DAoC to separate three sides from each other with a central PvP area. The reason is simple: Healthy PvP that isn't forced upon players.
If a smaller clan feels they cannot compete, there will be other directions and avenues of gaining these pvp based resources, in a manner that they wont have to go up against these super zerg guilds that usually inevitably form. Allthough saying this, it will mean they gain less resources, simply because they arent working as hard to gain it.
There will also be non pvp approaches to gaining resources, but again, as the players/clans that choose these methods arent putting themselves in as much danger, the resource gain will be slower than the players that choose to put their necks on the line to gain the best resource areas through murdering their fellow players.
Planning how your assets will be created is most likely your first step. While fighting with support to reset my world (which they are standing pretty firm on not doing haha) I have reflected on what you need to think about when implementing this system... here are my thoughts...
Bare bones fixed perspective camera:
1.) Buildings will need to be built with their roofs as separate objects.
Yes. I figure anything one story or higher that players could walk in/under would need to be constructed in sections unless they are by design not supposed to be able to view under(very rare use if ever).
2.) Scale will be important, most likely your character will need to be "bigger" then normal in order to not look "dwarfed" by buildings or other things in the scene
I noticed this already just running around my refugee island and the camera isn't even zoomed out as far as I would like.
3.) Raycasting from the camera to the character will need to be a must, if only for changing the transparency of anything that exists between the character and the camera (which is why we build our buildings and roofs for them separate)
Like Ultima Online, I would think an "area of transparency" that is circular around the player would be a necessary option, but not something on all the time. The fact that it can take away from people using objects as cover from view is a negative, but the positives far outweigh it in my mind, especially as names can be viewed by using "show all names" that shows the each name above everything on screen.
4.) Click to move, will need to be the best movement way, wasd will get confusing if the camera is oriented any place but directly behind the character, or careful camera and movement design will need to be in place to make movement not drive the player crazy using wasd.
This is something I will seek guidance on by those much more experienced than I. Aspects like this I was hoping programmers may find challenging/fun to work out, to a degree.
5.) I also feel like rather robust code to have the camera adjust correctly based on where the player is standing
will be more then required to maintain a usable fixed view. I feel like just having the camera "LookAt" the player object will be a disaster waiting to happen.
Also, you might be able to take extreme advantage of the "room" system instead of building your buildings with out roofs, but I don't know a lot about the room system. I think however you could use it to render only the inside of the room and not anything else?
Without roofs isn't necessarily a bad idea. Potential to use "building blocks" to create structures and just have the finalized versions combined into one solid model? If the building blocks/tiles aspect is possible it may lead to the possibility of customized housing in the future, much like UO added after a long period of time. Certainly not a priority, but it would be cool to have it as a possibility down the line.
Also again, my apologies for my snarky comments... It was not intended to come across that way, I frustrated at something else. You have valid questions and they should have been answered in a much kinder wrapper!
No worries, hopefully you were able to get your issue taken care of. I just wanted to emphasize that it wasn't going to be isometric, but 3d.