I think I vote Operation area expanded.

Also, the WZ2100 campaign is kind of a mix of both concepts - the base map keeps all your progress between separate levels and expands when new artifacts threats are detected nearby.
But to make that one work you need some sort of seamless introduction to each level, like Warzone had briefings that expanded upon why are you sending a team to a remote location or what needs to be killed immediately just outside of your base.
If that can be done I'll vote Industrialzone.

And now that I think of it, an air transport would make the fully separate levels a narratively viable option - just need to make the biters extra hostile so the reason you fly away isn't some arbitrary whim like "my radar picked up an abandoned base, I better abandon my base to check out that abandoned base" but escaping with your life and tech when the locals evolve and your base gets overrun. Yes, it'll give the mission a timer, but it's likely to be more than all but the slowest will need.

I absolutely love Expanding Campaign map, this is hella neato. You get to keep old stuff, but new technology unlocks and you slowly expands and beat new threats.

I think Commmand & Conquer did a simillar thing.

Got to say, I love the idea of the expanding campaign myself, but a lack of story would be killer for me, no matter what route you go.

I also liked the tutorials, though I felt they were a bit too limiting when I had to make X something a second, but was still limited to coal based production as a route power source, if you want me to produce something at SPEED, don't make me have to use a power source I have to micro manage.

I think option number 2 is the better of the two, however the very first mission REALLY needs to put emphasis on just HOW useful blueprints are, and how to use them effectively (Think, symmetry and smaller blueprints rather than HUGE ones), then option number 2 will work best. OR if it is possibly within the game's coding, building a new base at the beginning of each mission could be a different type of campaign, think "Beginners campaign" keeps your base between missions and lets the players run into problems to discover themselves their own mistakes from not thinking far enough ahead. Then a "standard" campaign for "players who already have some experience with factorio and want more of a challenge

[edit] as some other people have said, a good story, even if not comprehensive, would be helpful. Just a few avatars and some text (or voiced) characters to make you feel something would be nice :)

It always blows my mind how you guys keep looking at stuff that is great and just keep saying "not good enought".

But I guess that's the very reason why this game is so amazing. Recently played another game of the same genre, which I'm not going to name, and it felt really dull in comparison.
It made me appreciate better the exquisite equilibrium Factorio's systems have been designed, and how straightforward bust still deep and challenging the gameplay is.

Expanding campaign is my vote, definitely!

Just gonna note that the second design for the campaign (5 separate levels) is very similar to the way Kingdom: Two Crowns is structured. Might it be worth talking to the devs or players of that game to see if people like that way of doing things? Specifically in that the player must rebuild what they've already done in the past on all 5 levels.

THAT 500 players was funny as fook to watch. awesome job

Nice anthill you got there. :D

I finished the intro but there's no more missions, is the intro the only part finished?

Expanding map would be ok if the new areas had new sources of coal/iron etc or alternatively (and betterly) if each area had infinite resources of the relevant type only.

It would be best with a handcrafted map rather than a random seed.

I personally think a storyline could be quite interesting to pursue in a game like this, especially for any form of campaign. Freeplay used to have a little context of "We sent down an engineer with a mass of blueprints to colonise this planet for us, you are that engineer, get on with it and build a rocket" but it worked as an idea of why the player is around and has access to the sheer amount of blueprints available.

A campaign could potentially be a dive into the planet itself and an exploration of the biters and worms that inhabit said planet. For example. "You are an engineer that worked on a colony ship passing the planet. Due to circumstances of meteors or whatever reason that can be considered, it blows up and you and some other survivors escape down to the planet. Your task is to traverse the map as it expands from your crash site to the temporary colony the survivors have set up with a key building in the centre of the base. Then assist them in creating a rocket to escape the planet. As you travel you locate wreckages with useful resources, buildings, additional blueprints and even scientific data explaining the biters physiology, hive style, potential symbiotic relationship with the worm creatures and why they become more aggressive and stronger the more pollution is produced"

Tasks: 1: Set up a temporary base complete with radar and science dome to gather your bearings and locate any wreckages in your immediate area to expand your available constructions, fight off your first couple waves of biter attacks.
2: Work your way towards a signal broadcasting from an area outside of the radar's range, discovering it is another life pod and resting place of a poor engineer who landed close to a biter colony, getting overwhelmed and his constructions ruined. His landing area is tougher but has access to more advanced and quantitative resources, and his nearby wreck has the information of where the remaining survivors have gathered up.
3: Build a vehicle to get to the survivors fast enough. Explore around, deal with biter colonies and eventually get your vehicle to plow through to the survivors.

At this point I'll stop but even if it's less detailed than what I put here, it should still be around since otherwise you'd be playing random missions with no context, and what is the point of a campaign with no context or story? That being said it wouldn't be a good idea to make the story too in your face, since people said they didn't like forced tutorials. Make a small pop-up that contains a mini-tutorial, but can be removed and viewed later. If a player wants, they can just progress on with the objectives no problem, but if a player needs help it is available.

@Shadownamesto
That's quite a neat story though I have one problem with it. It sounds more like a survivor game, which factorio is really not. Also, I'm not sure if devs want to put so much effort in creating story and lore. I would suggest something simpler:
The Engineer is a specialist of Factorio company, which specialises in creating planetary factories to gather, process and send resources to human colonies (or Earth even). This planet has already several attempts to be "factoriezied" but all were unsuccessful, so the company sends their best worker. Due to rocket failure, the ships crash, far away from original landing zone, but also destroys most of the blueprints and equipment, so our hero has to start everything from scratch.

Factorial Fibonacci. I think this is an extremely graceful solution.

Why not both?

In the old campaign there were reasons for the character to be moving to new areas. You could have several different expanding missions that merge together.

Something like:
1. Landing
1.1 Crash; assess what happened, what you have around you
1.2 Fight some basic enemies to reach resources
1.3 Search for other survivors (scan, communications tower - special campaign asset)
1.4 Survivor nearby, need a car to get there quickly.
1.5 Try to rescue another survivor (plot point - they can die tragically or whatever)
1.6 Reach a piece of the crashed ship that has data about the planet and what happened. The ship was shot down by orbital defenses of an abandoned colony that didnt realize you were not a threat. Scans from the ship show a colony nearby. This prompts the character to move elsewhere.

2. Planning
2.1 Data from ship fragment indicates colony location, it is far away; but there are resources nearby to exploit to get there
2.2 Need to build a tank
2.3 Drive through infested region that is very dangerous, taken in stages where you can build a smaller base or connect things to the main base with railway
2.4 Clear shot to colony from here.

3. Setbacks
3.1 Arrive near colony, not quite as easy as hoped. Need to fly there or something. Initial base can be set up.
3.2 lots of aliens, need to defend things well.
3.3 Resources spread out over large area, need a rail network and defenses at various points.
3.4 Gather everything needed to build a plane that can take you to X

4. Arrival
4.1 Arrive at colony. No one alive there, but leftovers of the colony and of other survivors attempts to survive.
4.2 Restart nuclear power plant and other key systems. As you connect their base back together, you realize the colony was destroyed by aliens. The survivors were trying to salvage a piece of the ship and other pieces in the area, plus things they would manufacture themselves, to turn into a rocket to escape.
4.3 Retrieve and repair key pieces: navigation computer and guidance system, artificial intelligence, access codes for the AI, IFF from the colony to get past the orbital defense system.
4.4 Put everything together and escape.