Ah, the Borg, one of my favourite subjects. After posting some articles on the subject in this forum, I’m feel irresistibly drawn to comment on this matter. So, here’s my humble opinion on Borg colonization in BOTF mods
The Borg worlds we see on screen seem to be made up of assimilated populations.
In Star Trek First Contact, the Borg go back in time to take over the Earth:
WORF: Captain, ...Earth.
DATA: The atmosphere contains high concentrations of methane, carbon monoxide and fluorine.
PICARD: Life signs?
DATA: Population ...approximately nine billion. ...All Borg!
PICARD: They must have done it in the past. ...They went back and assimilated Earth. ...Changed history.
The movie clearly states that assimilation was used to take over the planet and its population.
In Voyager ‘Dark Frontier’, the Borg have developed a new method of attack on the Earth:
SEVEN: You intend to detonate a biogenic charge in Earth's atmosphere.
QUEEN: It would infect all life forms with nanoprobe viruses. Assimilation would be gradual. By the time they realised what was happening, half their population would be drones.
SEVEN: Inefficient. The virus would take years to proliferate.
QUEEN: We've waited this long.
It’s new nanoprobe virus, but the process of planetary takeover remains assimilation.
In Voyager ‘Scorpion’, Species 8472 is happily destroying Borg worlds:
BORG [OC]: Species 8472 has penetrated Matrix Zero-One-Zero, Grid Nineteen. Eight planets destroyed, three hundred twelve vessels disabled, four million, six hundred twenty-one Borg eliminated.
There is no talk of other populations in these worlds, they are all Borg, and hence all assimilated.
Assimilation seems to be the main (if not only) method the Borg of this era have to replenish losses and increase their populations. New worlds have their populations turned into drones and added to the collective.
In Voyager ‘Drone’, a new Borg method for growing drones is discovered.
SEVEN: I will be recognised as Borg. A drone, but unlike any I've ever seen.
TUVOK: It appears to be in the foetal stage.
SEVEN: I don't understand. The Borg assimilate. They do not reproduce in this fashion.
JANEWAY: Where did he come from?
SEVEN: I believe it was created here in the science lab. When the away team beamed back to Voyager there was a transporter malfunction. Our patterns merged briefly. It is possible that some of my nanoprobes infected the Doctor's mobile emitter.
TUVOK: They began to assimilate.
SEVEN: Yes. Nanoprobes are encoded to utilize any technology they encounter. Once it assimilated the emitter, it began to transform this diagnostic station. When Ensign Mulchaey entered the room, they sampled his DNA.
JANEWAY: Using his genetic code as a template to create a lifeform.
This ability to manufacture new drones from cells means that Borg theoretically can colonise barren worlds, instead of relying on existing populations to assimilate. But as this drone is effectively a 29th century Borg, this ability will not be available to the Collective for another 400 to 500 years.
So, what does all this mean for the game?
Given the current limitations in altering the AI and source code, the easiest path for modders to take is to use the existing colonisation subroutine and have colony ships colonise worlds like any of the other Star Trek races. It’s not accurate, but it’s easy to implement, and avoids any problems the game may have with changes to its normal game cycle.
Ideally, however, if you want to be as accurate as possible, then the Borg take over new worlds by assimilation. This means they do not have dedicated colony ships, but have their normal ships invade and take over a planet. How would this work?
Again, not knowing how far the current game program can be manipulated, I can only offer a theoretical model.
Any Borg vessel (instead of a normal transport as with other races) can attack a system (after the defending fleets are dealt with). The computer works out whether the system is taken or not (again as in a normal attack). However, instead of a reduced population at the end of the attack, a percentage of the initial population becomes Borg (as per assimilation). These are added to the subsequent Borg planetary attacks till either the planet is taken over, or the attack fails.
Whether this is currently possible at all, I’ll leave to the experts. Such a system means that the Borg are limited to inhabited planets only, when taking over systems. But this is not necessarily a bad thing, as it balances their more powerful vessels, and initially limits their expansion, giving the other players a fighting chance.
Factors to also consider in a planetary assault may include the type of assimilation being employed (whether microcircuit fibers, tubule nanoprobes of nano virus) which may affect the speed and percentage of assimilation and the level of resistance of the target species (ie the ground combat factors).
A mod set in the far future, ie 29th century, would not need to worry about all this, since the Borg development of cellular drone manufacture means that both assimilation AND colonisation can be employed by the Collective, hence colony ships can be used as per normal.