X4 is a good foundation, but especially combat gameplay and visuals could take some inspiration from its predecessors.
Why do I think that? To start this off, let me say that I have never played the first X, I started my way into the series back in the day with X2: The Threat and then went on with all sequels from X3 to X:R. My main focus on the game has always been the combat. Building a space empire is awesome and fun. Building it on top of the smoking wrecks of Xenon, Kha'ak and other opponent ships is more fun. X4 seems to have completely forgotten that there are players who also can't say no to a good fight. Yes, I'm just assuming that I'm not the only one here

Now, why am I telling you this?
Because X4 completely lacks the combat grandeur of its predecessors. In the previous games, combat was to a certain extent less a question of firepower and more about intelligent maneuvering and covering enemy weakspots. Using a longer range weapon and keeping one's distance was also an option instead of just going full pulse laser and simply overpowering an enemy ship. In X4, this has kinda been lost. X:R did ship to ship combat really well by introducing the capship gravity wells and allowing a player to work his way along the ship destroying surface structures. Capships were big, hulking monstrosities with enormous firepower but they all also were small levels one could play on. Somehow X4 removed the ultra long-range capship weapons of the Xenon and other capships and just made the pulse laser the universal solution. I miss those big fireballs with more than 10km range flying towards a station and wreaking havoc. While in other games you could outmaneuver projectile based weaponry, the 2-4k Meter/s weapons can't be evaded even if you have maximum spec modded boosters on your Nemesis Vanguard. Xenon seem to be an unorganized bunch, in other games of the series a Xenon Capship would sometimes come accompanied by wings of smaller ships, now a Xenon I just jumps through the gate alone and proceeds to get hammered by defense drones it can't seem to hit. Generally, enemies are a lot less intimidating, also capships are kinda small and poorly armed, where are the heavy guns?
This leads me to weapon balancing. The Space shotgun (80 MW output vs. Pulse that has 100-200 MW output with more speed and range???) and plasma cannon sink into irrelevance while Bolt Repeater and Pulse Laser are the only viable options for all ships. Beam weapons fill a small niche but are mostly useless unless fit on an L turret, they fail completely as missile defense on smaller ships. Weapon variety in X3 and X:R was awesome. Terran EM-Plasma Accelerators, ammo based guns, Shockwave Generators, Kyon Emitters, Point singularity emitters, Photon Pulse Cannons, Railguns, Heavy mining lasers, Chargeable Plasma Cannons with splash damage, Sticky projectile pulsers, where are those? Ego have previously proven how damn well they can make different kinds of weapons work and how creative they are. But all we got in X4 was the same projectile weapon with different speed and damage parameters. We can't use Kha'ak or Xennon weapons nor fly their ships, race-specific weapons seem to be gone. I think one major issue was taking the heat per weapon system from X:R. In X:R you only could have one weapon out at a time wich would overheat after abuse, they should go back to the X2,3 energy system, where a ship has an energy pool that get's depleted by all weapons at the same time, there was a good balance between the ships of different races. This worked a lot better with balancing for fighters and corvettes, turrets could keep working as they did before. With up to 6 main guns on a ship using different weapon types can become a managing mess with a weapon-specific overheat system.
I see that the combat mission part migh be addressed in the 3.0 Update which I am more looking forward to than Christmas itself, there is a lot of space for improvement and further refined combat would be a very welcome sight. Anyway, I'm having fun with X4 and the overall experience is that I'll spend more time than is healthy for me on this game. It's a foundation I'd be glad to see Ego build on, there's endless possibilities. This is just my 2 cents on a game I care about.