Yes, I've dropped (at least for now) the combinations ideas. Only some made sense to me. So let's do those side themes that make sense and forget about weird design rules.
From your suggested side thermes, most seem to hold very few techs. I don't think they can make it.
In the recent days, I've decided to go ahead with the proposal that seems easier to develop, which in my case is the following:
Five main themes with weapons:
- Biotec: all nature, genetic, neural, biochemical, tiny biobots and biology-in-general stuff, and some psycology (population, slow terraforming, env. tolerance, stockpiling, happines-cooperation, planet stealth, troops, research, industry, influence).
- Cybertec: advanced electronics, computing, androids, AI, implants (industry, research), cyborgs (env. tolerance, troops), drones, signal processing (detection).
- Crystal: subterranean (planet space and stealth, industry), asteroid stuff (industry, supply/refuel, hulls, planet defense), crystal (sci-fi trope) stuff (weapons and telepathy for oppression and influence, like mind-control, adoctrination, hypnosis).
- Energy: force fields and particles (shields, energy weapons and hulls, research, detection), star stuff (supply, industry, research), abundance of energy (happiness, cooperation), perpetual supernova (galactic wonder).
- Mech: mega and orbital structures (planet space, supply), huge machinery (industry), industrial and oppressive architecture, huge hulls, orbital structures (planet space, supply)...
Each will have around 36 techs (6 per tier).
The best theme-combination ideas will be reflected as techs of a theme that require some tech or tier from another theme.
Void theme: void stuff, all of it OP but expensive and with some sizeable drawback: void bomb that everyone hates, planetary stealth with malus to population, void habitation with malus to happiness, Enclave of the Void with malus to population and happiness on the planet it is built, void generator (industry) with malus population on the planet it is built, and I don't know what drawbacks I can do for a weapon, a shield and a stealth part.
Not a side theme, but more like a bonus theme, can go well with any of the main themes. Unlocked mid-late game, has fewer tiers and techs per tier.
Ascension theme (from
here and
here): transcendence process, energy metabolism, best planet shields, tech victory.
Unlocked later game, even less tiers and techs per tier.
This proposal is the one that scares me less, I've been able to write down some stuff in a huge table. Once it is finished, I think I'll be able to undertake the harder (for me) task of trying smaller, more numerous themes.