I think a lot of it is simple to fix in honesty. They obviously thought it was too complicated and took a lot of stuff out, maybe they'll just decide to chuck it all back in again. As it is, I love it, but I'm more excited about it as a "base" game for them to build on. Like Path of Exile.
It's rather amazing the amount of stuff they left on the cutting room floor.
Portals: In the game but not working.
Planet Rotation: Was apparently in the game if you believe Sean. Patch notes said he slowed down planet rotation even more after play testers got lost. I guess by slowed down he means got rid of it completely since planets don't rotate.
Orbiting planets: Not included. The stars are a skybox which is interesting since Sean was somewhat condescending towards games that use a skybox.
Factions: While still barely in the game they serve no purpose. You can be friendly with all three aliens despite the Gek and Vykeen clearly hating each other. Big space battles are actually in the game but it's always pirates attacking big ships and not the different factions fighting each other.
Planets: They were supposed to get more bizarre and challenging towards the center but that was changed for some reason. Plus sand planets don't seem to be in the game despite being in footage before release. The infamous giant worm creature has not been seen by a single player either.
It is rather frustrating that so much got cut from the game. I still play it some and enjoy certain aspects, but whenever I find a not working portal in the game, it reminds me again how much was never finished or not implemented.
Perhaps future updates can make it a better game. However, I'm not sure they will really bother with so much negative press and the huge amount of players that stopped playing.