I think the difficulty comes with the intricacy of detail. That extra complexity is the real challenge, the overall design of EVE isn’t really a factor.
In fact, to lessen on load on ccp’s end, they could actually offload some of the calculations for instanced dungeons to the player’s client. Nothing to do with game balance, but all that site dressing stuff, could absolutely be offloaded to the person who pulls the mission. Once it’s been assembled, the client would tell the eve server what the site dressing looks like, and the objects would be placed in space.
This would also allow players to have some controls on their end for how these sites look. If their computer is on the lower end, they could select to remove gas clouds, and a lot of the other unnecessary objects. Doing it this way, instead of just allowing the player not to render those objects, ccp saves load on the server, because those objects were never created in the first place.
This is actually why I want the static sites, such as around stations and gates (some locations even already have them,) they operate as the scenery you’re referencing.
That said, I also have a concept for how to incorporate planets into EVE gameplay. Planets and moons would create a mass shadow that would prevent warp, minimally within 100km of the surface of the celestial. Larger planets and stars might have a much larger area.
Furthermore, the mass shadow would create a warp scrambling effect around 30km from the surface. This serves as an incentive to fit both microwarp drives and afterburners on ships.
I would also put warp scrambling zones of control around some pois within the atmosphere, to serve as geography people would have to navigate around.
When pois are placed within the atmosphere and on the surface of the planet or moon, you’ll be able to recreate that more traditional feel in open world environments, because you have to actually travel to locations rather than just warp to each place you want to travel to.
As a side note, when you take into account potential vanguard interactions, all these surface pois (whether they be planetary interaction nodes or purely npc dressing) can serve as a beachhead for EVE to vanguard interaction.
And finally, when you combine this planetary construction with the mission generator, you truly get a feel for what this stuff is capable of.