Biggest issues to address
Just to provide a sort of overview for what I feel as a player should be the priorities to address. May be teaching the devs to suck eggs, but it might give a concise perspective of what the appears to be the biggest issues with the game so far, from an outside viewpoint.
1. Vital performance issues and 'Raid Recognition'
I'm sure the devs are aware of performance issues and game crashes (which are still happening after the patch) but what doesn't seem to have been addressed or acknowledged is the knock on effects of what I'm terming 'Raid Recognition'. This is when a 'failed' raid, either due to the game crashing, or the raider force quitting the game, or some other causes that are unknown but appear to exist, does not display either the raid stats (raid count, kill count, kill ratio and accolades), or the raid replay, or rather worryingly both, in which case you will have no indication a raid occurred on your outpost unless the raider decides to contact you and tell you they raided your outpost. (This has happened to me)
This is a vital fault that severely demoralises builders, and needs to be solved ASAP to retain players, because it feeds into the following issue...
2. Raid Promotion and community engagement
This is in reference to the fact that the format of allocating or distributing active raids to prospective raiders doesn't seem to be very effective. For one reason or another (possibly partially influenced by the raid recognition issue above) outposts simply to not receive many raids.
This may be a fundamental issue with having raids allocated to one of five genmat 'types' and sorted by three difficulty ratings, resulting in a pool of fifteen raids of which the receiving player will likely only choose either one or five of to potentially raid. This leads to 'stagnation' where outposts are allocated to raiders who will never choose to raid them. There may be ways around this without changing the format completely, such as tweaking how outposts cycle and are refreshed on a player by player basis.
Tangential to this is the sunsetting of mastered outposts. This is also fairly demoralising, although social raiding exists, it's not as accessible or well promoted. A limited system for reactivating mastered outposts in some capacity (such as a weekly mastered outpost slot or something) could be an option. Alternatively (and I'd argue this should happen anyway) heavy investment in promoting social raiding as well could make this less demoralising, knowing that there is at least a chance someone will raid your outpost without you having to personally and directly point them to it. This could be a more in-depth search system that utilises tags to find certain types of raids, and a bonus reward for participating in social raids, maybe a daily bonus or something like that.
These are the primary issues that will result in player retention or player loss for the game, and although not as urgent as a clear technical fault in no. 1, are certainly important to the longevity of the game.
3. Difficulty rating system
While the algorithm for determining the difficulty rating of an outpost seems very involved, and there are a ton of pitfalls I'm sure the devs have thorough experience with in the course of designing it, all I can say is it still has room for improvement, and there are a few issues I can already pinpoint.
It is very easy to create an outpost design that quickly jumps into Dangerous or Brutal rating, despite the fact that it is not difficult in the slightest. Conversely, it is also possible to build "unbeatable" kill box levels which are still classed as Dangerous instead of Brutal. These are significant issues for builders because Brutal outposts see fewer raids, and issues for raiders because avoiding Brutal outposts should result in avoiding the "unbeatable" bases.
I think this is largely influenced by the fact that the difficulty rating of any given trap is almost directly correlated to it's 'coverage', which is either it's detection range and/or the range it applies it's effects to. This means that a Claw trap has as much impact as a Boltshot, and a Holocube seemingly has the weight of seven Corrosive cubes, despite the fact that neither of these traps are lethal on their own. This makes it very difficult to use these traps without inadvertently jumping up to Brutal difficulty, and it also means smart 'kill boxes' can subvert the difficulty system by simply avoiding these 'large coverage' traps in place of more economic short range (but still deadly) traps, such as lots of Corrosive cubes.