So I'm 14 and change hours in, and i've been keeping track of my initial impressions of the game as I go along, as I do with most games I play. I played endless legend, but not endless space 1, so this is my first experience with this specific style.

TL:DR 

Really like the game. There are some faction specific issues, both in the playable and political factions, but the minor factions are what they are, they're fine. Pirates are hate-inducing

Faction Issues:

Vodyani: 

Alms for essence is terrible, feels terrible, and doesn't serve a purpose that I can see. It feels like a stop-gap in situations where you don't get an enemy to siphon, but the fact that it cuts all dust production entirely means you have such limited access to it that it's useless. If my start was terrible and I really need to use this to compensate, I'm done, I've lost. I'm not going to colonize fast enough, and this is killing both my dust production and ark improvement to the point where I'm too far behind. Honestly the Vodyani should be able to convert a non-Vodyani population to essence or some other method as a stop-gap, but this is brutal, and just makes you die slower with more pain.

Horatio:

The existing gameplay for gene splicing is counter to the playstyle that is provoked through the lore, and the earned bonuses. When I was playing the Horatio I felt like "I gotta catch them all". I wanted my population to have all the best effects; they had to be perfect. The food penalty was not supporting this. It was a brake, not a throttle. Instead of a persistent food penalty there should really be a conversion period. A time where you no longer gain population, and instead all your food goes to converting your current population to the improved version. No more population growth, and no more colonies until you finish converting all your existing population to the upgraded variant. Once it's done, everything goes back to standard and all new population are the improved variant at the normal food rate. You still want to collect them all, but each new addition is a growth throttle instead of an eventual full stop. "Do I want to use 60 pop of food for this new bonus, or do I need to expand in the turns that will take me?" There's a question, a decision that exists through the entire game, and it fits with the theme better.

Sophons:

Omniscience is boring, doesn't drive gameplay, and wouldn't be noticed if it were gone. Each of the other faction's major affinity drives gameplay in a certain way. I don't feel like I should be pushing science more than anyone else, because every faction already wants to have a research up all the time. I don't feel like I'm gaining anything extra for having completed a science, because I have no point of reference for how fast someone else is going, or even how much faster I'm going. They should be focused on the tech tree, yes, but something that's got some interaction would be better. Something like a discount on tech for every faction that's already researched it, with a bonus for being the first (which creates a choice) or something completely new, like a burst of science whenever you investigate a curiosity scaling with curiosity level (which drives exploratory gameplay). 

Political faction issues:

Let's see if it's just me. Does your political journey go Initial -> Eco/Science -> Military -> Science -> Military -> Science/Eco seemingly without regard to faction? Because there is the need to perform similar steps with each faction, I've noticed that no matter what my Political progression tends to that trend. I need to colonize so depending on whether the election happens right after I unlock the techs or after I colonize I push the election to the Eco/Science party's. After I need to protect everything so I unlock defensive techs (Which themselves promote military) and build ships, so the military faction takes over. Now we need to speed up our tech progression, so I'm working the left and right paths on the science slice of the pie. More ships now as I'm going to expand more. Now I'm expanding so back to the eco/science party depending on if my techs were already unlocked. It's repetitive, and in the early game there's little influence we can have on this.

Some of the laws are really good, and some are terrible. Why do I want only one type of population by law? Something that gives different bonuses depending on being the original race or not would be better. Vocational Caste - "+2 Inf per Original Empire Pop. +1FIDS per integrated population" 

And to get to the other point on the political gameplay. A law that progresses that political Idea would be nice: Proselytization, Military Propaganda, Employment Programs, Education Foundation, Conservation programs, Protest permit exemptions. Different laws that when in effect shift political opinion of population toward the selected view for each population of that view you already have.  

Pirates:

Pirates are a good way to create urgency in pacifying a faction and building a defensive army. However, they should not exist before turn 8. They shouldn't exist before turn 20 in my opinion, but they exist too soon. I've lost my initial explorer to pirates before turn 8 a few times now, and have had my initial system sieged before turn 15. That's absolutely insane. There needs to be a neutral faction spawn turn like in EL and when you pacify their "Home" they should stop spawning. Once you get to a certain point in system development they'll retreat from a siege, so the beginning of a turn from mid game and on just has this annoying repetitive beep as they use all their movement going from system to system, starting a siege (which makes the siege notification sound), deciding to run, then doing it again until they run out of movement. 

All in all a really good game, but a few changes could drive gameplay better, and make certain factions feel better to play.