I think the biggest issue with Starfield is they went with "realistic space" versus "fantasy space". Look at their other games, Elder Scrolls is a complete fantasy game with different races and such to choose from. Fallout, while taking place on our Earth, its setting is an idealization of the future dreamed of those in the 50s-60s. So it is still fantasy and does not match our true future.
It could have worked if they had created moment to moment better scenarios to create tension, mystery, and dread when exploring space, and scaling down the insane amount of lower end side quests(and repeatables), finding a way to decrease loading screens, and scaling down the planet count.
Speakable alien races not being in the game wasn't the problem for me. The problem was the amount of planets that were palette swaps with around only 10-15 unique repeatable interiors for enemy bases, creature caves, or abandoned outposts with aggro bots. Actual decent side quests would lead you to these locations, so there was no avoiding seeing the break of immersion and instead seeing a video game system.
Most alien species don't have their own identity when it comes to creating their own identifiable living spaces. For example on earth, you see spider webs, you know you might see a spider nearby. The main thing most alien types would have are egg-pod-things and not much else unique to only them.
Too many loading screens when entering, traveling to, and exiting planets, which is another issue of bad design that's mainly bad quest design(most quests took you off planet multiple times which meant constant loading screens). Also Bethesda games and item/menus/weight has been a consistent issue.
There is a way to help this game with a big bandaid, and I feel part of it is adding some sort of hardcore survival mode or something close to a rogulike. Games like Lethal Company, even without a group, all make the above fun. The mystery, scavenging for items to make ends meet or profit, surviving for dear life, the fear of the unknown when you land on a planet or moon. They nailed everything Starfield failed to in the moment-to-moment nature of the game.
Bounties felt flat, treasure hunts felt flat, scanning for new material felt flat, fighting aliens and bandits just felt like an annoyance instead of something to prep for and engage with caution. There was too many of all of the above. Too much bloat. Too many checklists.
The other part of this game happening in the big city planets should have had the majority of their quests happen
within those planets, to keep you engaged with them more often and really make you feel like you could spend a 'skyrim' amount of time only doing quests for only that big planet. It would keep going until you almost forget then realize 'oh wait, there are other big city planets like this, this is awesome'.
Instead, it's 'I need this from planet x' loading screen, get it, loading screen, complete, 'now I need this from planet y' loading screen, kill it, loading screen, complete.
At that point, the game might as well be a selectable menu of quests that instantly take you to the planet, the location, and the mission, like Mass Effect 2, because at least then we would have more well designed levels, encounters, and quicker loading.
This is why myself and others are mixed on the game. There is greatness and potential here, that could be salvaged with time, but it's wrapped in BS, loading screens, design choices from a decade+ ago, loading screens, and design choices that someone higher up would have to be humble enough to scale back on…and more loading screens. They're adding even more content that will boil down to being really cool sidequests split up amongst planets that may mostly be palette swaps again with minor differences and even more loading screens.
I will continue to wait and see how this game progresses both officially and with mods before picking it back up again. If that ends up being 6-10 years from release like Skyrim and No Mans Sky, then so be it.