We can't speculate about future science and say "this is believable because it seems like what we have now", that makes no sense because the real world has proved future technology is a thing we struggle to predict and can't ever imagine.

Yes we can. It's called verisimilitude. Theories based on existing paradigms, whether accurate or not, will be more believable. Of course you're right we can't really make any accurate prediction about a long-term future. Fiction shouldn't really be concerned with accuracy, but with immersion and believability. FTL is certainly within the realm of believability, but it's less believable than no-FTL.

Autonomious drone which also could be used remote. The Pilots are on the drone carrier.

If you think about it, wouldn't smart missiles essentially be autonomous drones anyway? Even if you chose to pilot them, wouldn't it be more effective to attach something explosive to it instead of a laser or whatever other weapon it could have? Outside of that, they'd certainly be more fun and realistic than "fighter" ships. They'd be even better in a FPS where you could get killed as a drone, and just hop into another one.

Did some brainstorming about it and got inspiration of scifi TV or movies.
A stargate SG1 episode. Where they remotely controle fighters planet side.
Avatar where even Character Get remote controled.
Farscape where pilot brain connect to ship systems.
Movie where you float in chamber having full spherical monitor view outside the ship and by Wii like gestures like bunch give fire commands and direction it must go. For the turrets with the best arc for that direction. You become the spacecraft.
Andromeda where fighter can be manned but also unmanned used.

So yes make sense a remote pilot could lead a sqaud of drone Fighters.

For interception for long range bogey these drones could stand High G force launch to get up to high speed for faster interception. Then manned fighter could .

Most weapon tech depend on huge engery out put.
So a drone with gunpowder gaitling gun and missile rack. When depleted of it few misiles it get much more agile and become fast dogfighter.
Bigger ships with there fusion reactor have railguns and laser
For railguns the muzle velocity and mass is in relation to the energy it needs.
Short low power railguns could be still much better then gunpowder. But longrail gun wher a gun with the same projectile get a long range canon class railgun.

This focus on A.I. destroys any game. I do not believe this 300 years ago people believe stuff. Even slower than light travel is almost impossible. Chemical engines run out of fuel in minutes. Ion engines have almost no thrust, light is even weaker. You can make up for that with lots of power (tritium fusion reactors are much more realistic compared to your ideas). Such a spaceship would accelerate like a fighter air plane. For days. With thousands of tons of weight. May we go from step to step and firstly reduce flight to mars to 1 day and then tackle FTL travel.

Have you read the papers about laser communication between satellites? Or how hard is it to hit the retro-reflector on the moon. This is all pretty close in space-terms , but on the front of technology. Laser communication outside the earth orbit is pure science fiction ..
.. and lasers as a weapon on that distance more so.

Of course already von Neuman knew, A.I. is the way to go. We do not need no humans (players or in space).

This focus on A.I. destroys any game.

Why? Me thinks AI make sense, also it is expensive by mass and spacecraft design to put humans in it. There still would be manned space craft the big ones but with lot AI support. Also if you using AI also the option of remote controle get possible. Fighters for defence and non FTL strike range could be piloted from carrier. As Mass driver weapons in space are more effective and also extreem long kill range add firing unit and foo if closing in to each other. Life expectations and combat endurance is very short for smaller space craft . But also medium. Drones make sense as warfare is more how fast you can produce or replace units. Numbers and war production.

I do not believe this 300 years ago people believe stuff. Even slower than light travel is almost impossible. Chemical engines run out of fuel in minutes. Ion engines have almost no thrust, light is even weaker. You can make up for that with lots of power (tritium fusion reactors are much more realistic compared to your ideas). Such a spaceship would accelerate like a fighter air plane. For days. With thousands of tons of weight. May we go from step to step and firstly reduce flight to mars to 1 day and then tackle FTL travel .

My guess is space warfare is fiction, it is unreal. Orbital satelite warfare as missile shield wel that possible . Near future it does not get excited much more. Unless some major bunch of technical breaktrough as making it also economical possible, putting some thing in space is expensive . Technological means does not mean it wil happen. Orbital warfare means orbit will become a orbital mine field by debri. Because it already is a bit due to ground to satelite missile test .
So realistic to me means a more science to fiction balanse. Because pure current day tech criple you so much it make no sense to go out there wage war.

Have you read the papers about laser communication between satellites? Or how hard is it to hit the retro-reflector on the moon. This is all pretty close in space-terms , but on the front of technology. Laser communication outside the earth orbit is pure science fiction ..
.. and lasers as a weapon on that distance more so .

You know it important at what audience you aim your game my bet is what game killer for nasa prof A could be not for nasa prof B. Because some can have different expectation of what the future might be. Keep in mind most of the target audience don't have high tech education so realisme is more about believability then the pure form. And take some or the most conveniënt fiction tech brake trough. Laser has compared to railguns a very far effective range against smaller and faster moving targets.
Gunpowder 7.62. Combat 300 meter travel time to target, nato bullit 1/3 1/4 second in space with no drag a bit shorter. Laser no drag you get 1/4 light second of combat range.
Sniping nato 7.62 800m in space you keep you muzle effectivity so it moa distance to target size and agility 5 seconds that realy far.
5 seconds for a heavy laser canon attack a non agile vessel 100m large 20 m wide on 5 light seconds.

Of course already von Neuman knew, A.I. is the way to go. We do not need no humans (players or in space).

I would keep this but will have humans in space but at a cost.
Also keep in mind a 1km vessel doesnot mean the crew can move in that 1 km only crew compartments. And those compartment can be very limited. Like 5 to 15% of the vessel. The constructor is free to make it luxory for civilian or as spartan for military Vessel .
Altho Nimitz naval carrier are a few 100 m long with a crew of 5 K.
In space it could be 1 km and a 250 crew but wide mix of 25.000 Drones .

Well i take the soft scifi games and movies and series as reference and make some features for game more realistic as it fit the game is fun balance . For intterstallar trading there just need to be FTL.

What make no sense to me is take real scale space and go for fighter planes in space Combat with a speed limit which is very low for space. Because its online game. Cripple it more to make it more depth and slow pace with turn handicap.

Most milsim game are still game then a true mil trainer. Space sim might need much more compromises .

I just meant A.I. breaks the idea for me because it improves at a rate far higher than space travel. Before space battles gets remotely interesting, A.I. will have surpassed most humans in intelligence. As I have just seen Star Wars, their solution is not to be realistic, but to somehow level all figures in their intelligence. It's like the soap "friends", where friends by purpose interact with people with similar intelligence. I understand that you mean realistic with respect to speed of light. But please copy the Star Wars solution, where everybody has their smartphone -- eehm -- I mean Nav Bot, and technological progress is frozen.

A battle for what? What resources are limited when you can travel the whole galaxy? Now it is like the first time humans explored America.

What resources are limited when you can travel the whole galaxy?

Well, by that extension some elements are rarer and more useful than others.

The original American pioneers didn't travel around the country hoping to find iron, they mined for gold and it was rare and valuable.

Similarly the universe is infinite and the galaxy vast, but you wouldn't travel it to bring back or refine heavy water when it's available from comets in your back yard.

You might travel the lengths of the milky way for some new rare element required for space travel though, or to fight over the limited few habitable planets that are light-years apart. If there is a planet within sensible travel range that has an earth like environment and all others for dozens of light years are like Venus and Pluto, then too right people will fight and die to be the company/government/privateer to own them and levy taxes on their occupants.

Lots of space for plot if you step outside the solar system...