This is the greatest news I've heard in GameDev so far. One of the drawbacks to replayability for the game for me is the master tech tree. It's incredibly repetitive to research the same basic tech tree no matter what species you choose to play in the game. Each species should have it's own unique tech tree based on unique characteristics of that specific species. For example, the Bartak Grove are a sentient plant based species and should have all organic techs based on living plants. They should have extreme bonuses in their tech tree to agriculture and have living space vessels that run and store solar power. Even the ship design, weaponry and defensive systems in the tech tree should be curtailed to the species. They should be the exact opposites of the Yor Singularity, which is a sentient computerized A.I. species. The Yor's tech should have bonuses to construction and digital adaptations. They should have no need of agricultural techs and should have bonuses related to collective processing power, energy consumption and high tech weaponry/defenses. 

So, yes. This. A thousand times this. I've wanted to see this for so long in the GalCiv universe. Completely unique species with wholly different tech trees, adaptations, ship and combat designs and so much more that would make the game immintely re-playable without getting bored of researching the same tech tree over and over again.

How about an aerial species that can only colonize dead/gaseous planets. Or just build starbases/cities.  Think Yorktown in Star Trek Beyond. Or lives in nebula. Or can travel into/out of black holes. 

I want gaseous, but they have to be able to colonize gaseous planets that are dead for other races. Other races might invade them but all they can do is to wipe the inhabitants with no way to live on them. All the planets need to have different life expectancies based on the species colonizing them. Maybe even if something basic like -80% all production if not wanting to do the "can't live there at all"

Symbiotic life forms: Capable of merging several different forms of life into something unique. Such as lichens on trees, which are a mix of fungi and algae. Their symbiotic relationship equally benefits both life forms and enables them to adapt and survive in environments that they would not be able to live in on their own.

Protozoan: Another of the official Kingdoms of life in Taxonomy, Protozoans are life forms that display both flora and fauna within them. Both the best features of plants and animals. They eat. They consume things. They also photosynthesize and poop. Sometimes at inconvenient moments.

Ephyphitic: Ephyphytes (air plants) are plants that exist outside of soil, preferring to cling to objects and derive all of their nutritional needs from the atmosphere itself. Spanish moss is an ephyphyte, think intelligent Spanish moss. This might fit in quite well as a concept for a species evolving in gaseous environments.

Fungal: Darkness is Void; Juffo-Wup is light. You are the non. 

Energy: Light exists as both a particle and a waveform simultaneously. If energy is never truly lost, perhaps it exists in alternate dimensions that can impact ours. Could be a good lead in for multi-dimensional energy beings, spirit species or just a hyper-intelligent shade of blue. 

DNA: DNA and RNA have been proven to exist, persist and survive independently of life forms. It exists in soil. It exists in water. It existists in air. It's a source of organically coded information which can, presumably, be read and learned from. How weird would it be to have a species that exists as nothing but a massive strand of DNA. DNA that could be inserted into an organelle to serve a purpose. RNA that could be inserted into a virus as a weapon, etc..

I could probably come up with a few more weird ideas but I hope a few of these helps spark your imagination. 

I would like to see influence only affect similar biologic species or require late game tech to affect other life forms. I dont see any reason why a non-aquatic based species couldnt live harmoniously on a planet in the same solar system as an aquatic species without them culture flipping each other's planets. They are very different, cultural influence should be applied differently.

Also, War should severely reduce the cultural influence of an enemy, or during war give options for xenophobic war propaganda to reduce foreign enemy influence.

I think Influence has been one of the least developed game aspects and has much more potential.

Off topic, can you contemplate being able to research two technologies simultaneously?

Right now there are what four color coded trees? Have one tech selectable from the Red & Orange Trees, and one selectable from the Blue & Green Trees.

multiple energy beings - can only colonize stars rather than planets - colonization of new stars can only proceed slowly via the harvested accumulation of stellar energy that is combined with elerium and antimatter in sufficient quantity so that the multi-energy beings can instantly hypertransit to another chosen star - elerium and antimatter can only be acquired by species which space travel,  whichever species gifts the critical amounts 1st  can designate which star the multi-energy beings move to.  Once the multi-energy beings "colonize" the new star, that star becomes immune to the terror star destruction (which means that the inhabited planets can only be conquered by invading them)

If you ever add espionage into the game, changeling would be a good option to introduce with that mechanic

I'd rather have all biology be decided by the founding species of my faction's citizens and then be able to create custom citizen species ingame instead of using mod tools.  Then every citizen would have one of those biology traits + the kind of traits they currently have.

(I don't think this is necroing a thread as it is still relevant)

I think the Gaseous got turned to Ammonia as best it could?

I've been thinking "Code-based". It's not Synthetic or silicon. It's not made of material, it's based on re-generative adaptable coding which has absolutely no limitations and doesn't have a specific form, shape or optimal environment. It can generate whatever form, shape and durability a world needs to function. It can also survive into objects for an amount of time(like it could transfer and/or replicate tiny bits of tech to form a PC type device on a piece of wood) but is self transferable and attempts to take over Galacticivs it finds in outer space. For the same reason its difficult to die, so one can't be sure unless they completelly destroyed their every trace. And then even they could survive in a transmitted message or something(that would make techs like jamming more useful against them in securing there isn't anything of them left out that could help them rebuild).

I'm thinking they could prey on minor civs in particular. One turn you see a peace loving minor you can trade with, the next you're suddenly at revenge war with a formidable foe you thought you eradicated.