"Is that so? I'm always having hard time dealing with HIVE."
 For my 1500+ hours in ROTBP/SL when i see HIVE against me i never thought:
"Damn they picked HIVE , it would be tough match"
When i see HIVE pretty much always she is easy frag.
She is one of easiest characters to deal with no matter who you pick ,
just monitor where she is and dont allow her to get close , thats it.
There is no need to pick her when Lycus exist , same role and playstyle but overall better than her.

"Doldren? Well... ok. Harec? Maybe.
But what about Shae and Iune?"
Any Local counter her with ease , thanks to extremely good talents and damage.
340-500 hp is nothing for locals and can delete HIVE with no problem while HIVE only tool what allow her survive is Shy protective bubble.
And they can also easily beat HIVE in CQC thanks to talents again.

"Choosing a melee fighter on the map for a sniper and complaining? Seriously?"
There is only few stages in the game what allow HIVE to feel decent.
First stage of Breath of Hope(maze) and White Noise are only ones where she feel very good.
Other CQB maps and stages are bad for her due to poor spawns and objectives. Raiders can easily spawn camp her and rush objectives with ease.

"But all characters suffer from MMR , poor spawns and objectives!"
Yes all suffer , thing is if this issues will be addressed all characters will be indirectly buffed.
For example:
HIVE current "strength" is 5 out of 10 , other characters 6-7 out from 10.
After this issues will be fixed , HIVE would be 6 out of 10 while other characters would go 7-8(just example).
She have fundamental flaws what cant be fixed by skill and current talent roster is very lackluster.
She is pure CQC character in the "gun meta" state of game , plus add how  buggy and inconsistent CQC is(I dont think CQC will be ever fixed)

HIVE is melee character who sacrifice everything else to be effective in one thing , CQC.
Problem is how easy to counter her and her overall lack of tools to respond to this counters.

There so much hard counters what not allow HIVE survive , not even win.
HIVE get completely shut down by
-Any Local
-Push-stagger weapons
-Area denial weapons
-Aleph bombs
-Maps and stages what not allow flanking or manoeuvres

All this make HIVE unviable most of time as Antagonist.
She is good Raider because there always entities what can be leeched for essence gain plus support from teammates.

My MMR is 58 and i judge her from more competive/high difficulty aspect.
Things what you point out is indeed true but its only is at low-mid MMR and difficilties.
She indeed  "30 MMR beast" and against new players she is very good but she fall flat at high MMR and skilled opponents

It turns out that the problem is not in HIVE, but MMR

Hello there, Nin'Mug!
I've read your feedback and your ideas are quite interesting! Thank you for putting so much effort into this post!

The thing about H.I.V.E is that she is a close-range character. Being part of the Wardog, she heals really fast,  besides having a special ability to increase her base health. She is basically quite good in what CQC concerns. "Shield coating" give her a more mid/long-range approach, being able both to endure snipers shot and CQC, which reminds me of the 5th council base characteristics. She would be probably the strongest character of the game (destroyer at a close range and quite unkillable on the mid-long range).

I'm concerned that that wouldn't be quite fair for the rest of the Raiders!

First off, thanks for game, it's great!
Devs, I want to talk about the game, the psychology of people, money, and other interesting things.
Spacelords need improvements. This, of course, requires money. In turn, to make money, you need players who want to buy something from you, and the more players (and purchases), the better. The logic is straightforward and simple.
Here's what I think might help you. First of all, about what is easy to do and what has a greater effect.

1. People DO NOT like to wait.
Your cutscenes are great, but don't make people hate them. The joke told 100 times is not funny anymore.
I suggest that the very first playthrough of each mission should be a solo game. Set the difficulty to a minimum, so that the mission is something between training and real multiplayer. Check each mission so that it can be easily completed by ANY character.
So player can enjoy the story, cutscenes, and get familiar with the mechanics of the mission.
Further, starting from the second playthrough, everything is as usual, only game start needs to be made as fast as possible, without cutscenes (you can put short information on slide before the mission).

2. All people are DIFFERENT.
Yes, I can't ignore the MMR. I understand you wanted to balance the game. I could write a lot on this subject, but I think that you already know: the system simply does NOT work. In fact, it could NOT work. EVER. If I ask you - "what is balance?" - you will give one answer. If you start asking people, then everyone will give the answer, and all answers will be different. And if you try to equalize all people with one system, without the possibility of choice, and flexibility, you'll get a FILTER. So you've filtered players ... why?
Unfortunately, instead of a reward system, you ended up with a punishment system. At first, you often win, quickly pass missions, for which you get a high score. Then it becomes more difficult to play, missions are completed slowly, the score is lower, rewards goes down. This is ridiculous.

Everything has already been invented, it is enough to adopt successful solutions. I propose to introduce a "tiers" system. It will allow:
- Different groups of players get the desired gaming experience (casuals just run around and have fun, hardcore players get a challenge, etc.).
- Get a sense of progression, upgrowth.
- Freedom of choice.
- Sense for leveling.

0 tier. Training. Opponents have 50% HP, -50% damage, and the number of opponents is greater. There are NO antagonists. Just fun'n'meat.
Max. reward - 70%.
1 tier. Normal difficulty, like MMR 30.
Max. reward is 100%.
2 tier. Difficulty 20% higher
Max. reward - +20%.
3 tier. Difficulty 20% higher
Max. reward - +40%.
And so on. Figures for example.

Important - raiders' weapons should not receive bonuses or penalties any more and ever (if enough people in queue to start game).
The antag, on the other hand, receives a penalty from the difficulty:
If he joins tier 3, then no penalty (for him, the difficulty is normal, for the players - high)
If joins tier 2, 20% damage penalty and CQC (for him, the difficulty is 20% higher, for players - also 20%)
Etc.

3. People love personality.
I propose to introduce customization of characters - hairstyles, make-up, jewelry, backpacks, etc. + ability to change color.
And sell for mercury points.
It should also be possible to assemble the necessary jewelry or accessory (and maybe a hairstyle) from spare parts that will drop out at a high level of difficulty on missions.
Profit for you. Interest in playing and leveling for players.

4. People love constructors.
LEGO is still alive and well. Why are we worse?
I propose to introduce a system of cyber-implants for characters of various qualities and with various properties (for example, +10% speed, +10 armor, etc., a small but pleasant bonus).
For a start, 2 is enough for each character.
These implants should be assembled from parts that will drop at different difficulty levels. The higher the level, the higher the quality, the higher the bonus.
Again, parts can be sold for mercury points.

5. People get bored playing the same game over and over again (unless it's CS or Diablo, LOL)
I propose to introduce level variability.
What if, for example, when the characters enter the elevator, Cortez shouts - “Run! This is a trap!” ... But, of course, it's too late, and the elevator goes the other way, another map is loaded, players must fulfill certain conditions in order to turn elevator back. The probability of such an event is, say, 20%.
You can imagine of a lot of very different interesting situations. Tell me what you think about it and if you wish to know about my other ideas.

6. Little things:
- Introduce the highlighting of characters suitable for the mission.
- Daily Objectives - Kill 50 CQC opponents, or with a crossbow, or kill 30 Elites...

I can describe everything in detail. Let me know if interested.
Thanks!