After having played quite a lot to Endless Space and appreciated its gameplay, simple in its gimmicks but interesting to exploit, I now understand the reasons of the lack of variety in its planet-generator system. However, I don’t think that adding a little plus to it would break the balance of this element which has lots of implications on the rest of the game : some games like Borderlands 2 are able to definite rich but understandable and exploitable generator systems, because they can divide these systems into very simple phases. In this thread, I will expose in several parts the gameplay implications of each part of the planet-generator system of ES2 and then I’ll try to show how it could be possible to add variety to it.

I) Endless Space, a “gameplay-oriented” generator system
II) Deconstruction and reconstruction of the system, new ways of thinking

I) Endless Space, a “gameplay-oriented” generator system :

In the first opus of the license, a planet was characterized by a sum of elements :
- Its Tier (influenced by the star of the system), which conditions its harshness and its access in general (with Tier I being the easiest planet to colonize and Tier V the hardest) ;
- Its Type within the Tier, which define its base FIDS production and its approval reduction effect on the system. Some technologies and buildings have specific effects on a planet type (for example the Null-G fields and Condensate system technologies for the Pilgrims and the Amoeba are only useful for gas giants) ;
- Its Size, which define the population limit on the planet. Some buildings or capacities (like Crowded planets) can have effects on planets of specific sizes ;
- Its Moon (or satellite), which can be existent or not, and can have a endless temple or not (with once again some buildings adding effects on moon-possessing planets). A planet can only have one moon ;
- Its Anomaly (positive, negative or non-existent), which modify the fids production of the planet, the approval in the system or, in the case of endless and natural wonders, can have more particular effects ;
- Its Resources (strategic or luxury), which can have various effects (in ids production for the first, in other domains for the others).

These six elements can logically be randomized (the Type, and only a little Size, being the only dependent elements in the creation procedure) to obtain a fully functional planet in the game, and it’s perfectly possible to modify the probabilities in a game preparation for some elements.
We can see that this system is really simple to understand, nearly each faction being specialized in a type of planet, it is also very simple to use terraforming to quickly adapt an empire to specific strategies. In short : this planet-generator system is “gameplay-oriented” (and it’s also a good way to lighten the game in general).
However, its pro is also its main con : its simplicity can be perceived as a barrier in a game where eXploration is (must be ?) very important, and it is even truer in Endless Space 2, where the new systems of populations and votes are indications of a will to add complexity (is it now eXplore, eXpand, eXploit, eXterminate, eXplain to your population ?).
We can also add another element proving that some modifications should be done : the lack of logic for some anomalies (have you ever seen a Garden of Eden on a lava world, or The Tree of worlds on a gas giant ? I do regularly…).

II) Deconstruction and reconstruction of the system, new ways of thinking :

As I said, it is very simple to deconstruct the system of generation. However, in order to make it more complex without making it less usable, some thoughts must be put in its reconstruction : new aspects could have importance :
- The type of the star (blue, red etc) ;
- The states of a planet (barren, lava etc) ;
- The composition (in simple ways) and the strategic resources ==> not enough elements to bring details, but a gas giant should not have hexaferrum in it for example…
- The planet’s size ;
- The potential number of satellites ;
- The phenomenon of life (for specific anomalies like Garden of Eden) ==> would it be possible to have a jungle world just next to a blue star ?
- The asteroids (for anomalies like Meteor strikes).

Two elements will be detailed here.

The star :
In the first opus, the star can have one consequence : the tier of the planets in the system at the beginning of the game. After that, the distance to the star isn’t taken into account for the planet distribution in the system and for terraforming (a jungle world near a blue star… why not ?).
In order to make things more logical but not too complex, there is two solutions for me :
- A measurable distance could be applicated to the system (like a ruler on the side) and, depending on the distance and the star, the distribution of “Tiers” could be done at the beginning. The modification of the distance (represented by enormous amounts costs in industry ) could be a condition to terraforming for some specific types of planets.
- A simpler condition : depending on the temperature of the star, the planets near or far away from it in the representation of the system can’t have access to some “Tiers”, and the terraforming of these planets in the late game could cost more.

In these two cases, the main effects would be to eliminate “Tier I planets” from to near-sides or the far-sides of a system, to make “Tier II” ones also more centered to make gas giants and asteroids appear to a respectable distance from the star.

The state of a planet :
Following the precedent section, this one is quite simple : what could be the criteria to make a rocky planet a lava world, an arctic world or a barren one ?
The distance to the star should be once again the first element that should be taken into account : a planet next to its star shouldn’t be arctic, except if the star is a dwarf maybe. To make this first parameter applicable, I think the best way would be to take into account the "habitable" zone around a star (with one of the two methods described in the previous section).
The second element would be the composition of the planet and its size (for example : lots of heavy metal + medium size + not too far away = lava planet). These two parameters will be described in the next sections.
Another thing will be the proximity of the planet to an asteroid belt, or, in the case of a satellite, the gravitation around a massive gas giant (for example, a planet which, because of its proximity to a belt, suffers from numerous meteor strikes, has a higher chance to be volcanic than to be arctic).
Finally the strategic resources (which now functions like in Endless Legend) should influence or be influenced by the composition (cf heavy metal planets).

As a conclusion (and because I think this begins to be very long and needs to have a sum up), my basic idea is to go from this schema of creation :
(Star => Type => Size) => Moon/Anomaly/Resources altogether

To this one :
Star => Position => Type => Size => Composition and strategic resources => State => Life or not/Moon(s) => Anomalies

So, what do you think of this (I know that it lacks details, but we are so uncertain about what will come in the near future that only approximations can be made right now...) ?

P.S. : Some elements I made reference to can be found in Stellaris, but the game came out after the beginning of the redaction, so I didn't copy... It even proves that these elements can be used without problem.

You are late to the party. Maybe start with reading GDDs ?

It appears that GDD3 is the only one I missed ;(... Some elements can still be taken into consideration : the appearance of strategic resources could be linked to the planet types, the appearance of life (and so organic luxury resources) should not be obligatory on every "jungle" or "forest" planet (but I understand why they named them like that : it gives a good idea of the climate...), and lethal stars like blue ones could influence this last probability (not because of temperature, but because of the light they emit : Sophons, who begin next to a blue star, should consider themselves as blessed, and other planets in the system should be quite dangerous).

Finally, we still don't know about distances in systems : will temperature only be modified by the star of the system, or will the order of the planets in it contribute to it too ?