As the title says, the Deadeye enemy just isn't fun to fight in it's current state. It is a great enemy concept in a vacuum, but in execution with other elements of the game its just frustrating.
It is by FAR the most oppressive enemy in the game currently, demanding your attention if any are in your area. No other enemy in the game forces you to have a counter in your kit, as it should be. I do not want to take something because I have to, I want my kit to be built the way I want to build it. The majority of primaries and spells in the game have little to no effect on the deadeye, which makes this next point all the more problematic:
They have absurdly high health for seemingly no reason, and its never fun when an enemy has high damage, mobility, AND health at the same time. It is sort of the flying overseer problem from Helldivers 2 all over again.
The biggest problem overall is the shot however. It is effectively hitscan, meaning you are taking guaranteed damage if it fires. Easy fix, just flinch it right? Well, no. In the difficulties it spawns in theres already so much clutter on the screen that it can be damn near impossible to see where they are, even with the indicators. But even if you can, SNAKES man. It almost feels scripted that any time there is a Deadeye taking aim, a snake will jump you and gauruntee you take the hit. But even outside of all of this, multiple can be around at the same time- I commonly see 3 at a time, and it is just frustrating. Trying to flinch all three, with all these aforementioned problems, all while knowing its going to take multiple magazines just to get all of them out of the sky... it isn't fun.
All these problems compound DRAMATICALLY in solo, making these already crazy oppressive enemies even worse. Solo is substantially less fun because of Deadeyes.
I am not a gamedev so I don't really know what would fix the issue, but I think making the shot a projectile instead of hitscan would go a long way- as well as reducing the health. I think nightmare is fun because the game becomes a bullet hell, but then you just have this one enemy that breaks all the rules. I really hope we can get a rework for this thing, it is a cool idea but it needs better execution.
UPDATE:
I have grown more used to their attacks and don't mind the health and hitscan anymore- it just took getting used to after having free reign in the playtest. I do, however, still think that too many spawn in solo as you cannot ask a friend to help flinch the Deadeyes if you are being CC'd or overwhelmed. Spawnrate reduction was already discussed, and I think it would be helpful to have their spawns tweaked in solo and 2-player gameplay. With 3 and 4, it isn't as much of an issue.

