And I see you're absolutely ok with stealth being partially broken.
But I'm sure everything will be fixed in time... I just don't understand why everyone is denying or belittling problems and partially broken systems.
If anything should go into A19.1/2 should be these kind of fixes IMO.
I mean, it's alpha, as Madmole said you still need to wrap up some of the main systems, so there's no shame to admit that some of them can still have bugs and/or broken parts that are evident while playing. But I feel like I'm beating an undead horse so I'll stop here.
The reality is, there will always be mechanisms in the game that are left to abstraction aka broken for anyone not accepting the abstraction. Improving them also depends on whether there is actually a way that doesn't cost too much developer resources or fps.
I actually think your list is a good checklist of (optional?) things that could be improved about stealth:
Those heli landing spots on tier5 buildings are especially bad at spawing zombies in plain sight. I would add generator boxes or a lowered service walkway around the heli platform. Some other POIs could be improved that way as well. But they probably don't have the time or intention to fundamentally change the spawning mechanism. They probably can't prevent spawns in plain sight in each and every case. By the way: I am calling it "plain sight" even if the spawn happens just when I don't look at a spot for a split second.
Your point 2 (light that pushes the sneak meter up but nothing happens) might actually be a real bug, but did anyone make a bug report with reproducible steps? Because detection is random, this isn't easy to prove or disprove. Is it really a bug or just a situation that leads to detection only in 1/4 of all cases? You claim it is broken, but you left out any evidence.
I'm relatively sure they won't improve it to the point where shining a lamp into a zombies eye would be different than having it turned away from the zombie. This costs FPS. It sadly also means that a zombie will react to the light the same way whether a wall is inbetween or not.
Point 1 (sound of arrow impact is ignored) is problematic. If you simulate arrow impact sound you must also simulate bullet impact. That might be ok for the hunting rifle, but once 8 people on horde night shoot with M60s at the zombies that rather simple check might generate a big drop of fps.
Generally, the Dev Dairy is not the place for bug reports. If you make hazy claims, expect hazy replies.
So how is a sneak attack with a knife ever supposed to be effective if they always wake up before you can get within 1m? Is the knife reach actually longer than 1m?
In A17 I stealth-ran to a distance near enough for the knife and immediately tried to cut their head off. Did not always succeed but often enough. Since then I was busy with trying out other attributes so not perfectly sure if it still works, but generally weapon reach now is greater than in A17.