Well I know this is expansive but this idea is to be implemented over a range of updates/expansions and the methodology or plan of pace should be covered in construction.

Quickly in short, temperate will be the first planet out the door with 2-3 locals at the start.

As every expansion comes out a new planet with two locals will be introduced with +1 local to the planet with the fewest number of them.

Zone borders open up on all previous PVE places as new locals are added.

Every New Local will have a finer tuned PVP matchmade map set to ship with it as well.

Weather can be shipped independently as they get done. Planetary effects will be the first ones brought in and should ship with the planet.

I went with zone borders saves us the trouble of having to make planet sized maps; though you can still advertise in the distant land box where the zone border or transitioner would take you.

Zone borders in open world mode would be more of a yellow zone stay in it too long and you then automatically transition to the next zone though some maps may have choke pointed area.

Loading Screens will be hidden by animations luckily (You walk into your VAN and an RDV picks it up to transition it)

As for the lack of people option eve online space already suffers for that but also doesn't suffer for the following reasons.
1. Players give purpose.
2. A culmination of perfect conditions makes the place popular.
3. Lay of the land makes it strategically important.

Now relying on these three means that 'there will always be places that nobody ever visits' which is fine, some folks like to be left alone and do things without anyone screwing with them... hopefully. This also may create the condition of crowding in some of the more popular areas.

But lets modify the 3 for our needs

1. Players give purpose - Purely Dust 514 alone this would mean setting up a corp HQ, building your base and changing the layout of your base, the function of your base, and now you have to run and maintain this base and keep it protected. You have now given this zone a purpose, its home, its your money maker, or its your safe haven vacation spot after a long day's of grueling mercenary work. This is also where Eve online has the MOST room to wedge itself into for future link.

Industrial player sets up a mission - Help my PI extractor work. mission could be randomized from simply fixing the damn thing, killing saboteurs, or heck nothing at all than to baby sit it.

Military minded players could set it up so that they can tap into the military equipment surface side or facilitate the installation of it.

2. This can be done by modifying NPC populations, Events, Security status, Planet numbers in system/constellation/region, or nearby market hub for the rarer materials or NPC services, or even better player services.

3. And finally strategic importance. Dust side it could be as simple as taking out an HAV factory that is making cheap tanks for your enemies.

With Eve Involved - Plasma Planets for example could be the only planet type that can host a System wide cyno-jammer, It is a plasma planet in a solar system perfectly placed that no other nearby star system allows jumping access into the defender's constellation; the heavens and earth will move to try to take this jammer out. Expect multiple invasions and orbital fights to bombard that structure into nothing or capture it with foot soldiers in the respites between bombardments.

There are also other ways to make players visit the places often as well. One example is to make the Salvage Game Mode use the open world zones despite that you are going there through queues. Another possibility is making the PVP NPC matches also take place in open world zones (to facilitate this, the map will always have x number of players reserved for this function so that no matter how many third party folks are there the two teams can still duke it out with full members)

Pvping players may wind up in a neat zone and go; dude I want to go back. Dial in System Planet Zone and you're back in that area for open world and free to do whatever.

Another thing we can do is populate only few of the planets, not ever planet needs a zone yet or may not get one until conditions are met (lacks elevator for example) Some zones only open or close depending on condition (all Starbase and Station Zones for example only open when vulnerable) There are many many many tools and tricks to help the zones feel a bit more alive even if you are the only one there as well.

Its DAME unfair how Legion gets all the fun stuff while Dust doesn't. I don't like using bad language but its just unfair. Look at other games. They have alot of stuff but in Dust oh no it can't because have Minmatar and Amar HAV, Dropship, LAV, ect..and maps because its limited. Was MAG limited when it was released NO, how about The Last of Us NO, Killzone 3 NO, or how about the Uncharted series Effin NOPE. I can keep going and going about how the ps3 is a console that has been pushed and that's what Dust needs to do. Push it to the limit, use every thing in the ps3 system and in the end Boom its possible.