Hey there,
After 3 attempts to play through the game (and really starting the 4th one 
) I have some thoughts and suggestions for the devs (and the community, of course).
First point – Explosive Chirons and Sirens:
In my last try to beat the game those beasts just ended everything for me. Coming from the other corner oft the map, having infinity (?) range and explosives that kill even good geared level 7 soldiers with one hit that for sure is a game breaker. So really I hope you will find some way to rebalance those. Same goes for Sirens. Willpower should be used for defense vs mind control so you have a chance to avoid it.
Second point – Lairs:
I know there is already a long discussion so I will keep it short. Endless respawn is never ever a good thing and should be avoided. Yes, its in their territory. Yes this game is not Tetris, its a tough and challenging one. But just consider to limit the enemy numbers. That way one can beat them either by speed/rush or fight the way through them without taking it hours (or just failing it over and over again).
Third point – Overwatch:
It is cool to have overwatch. It is not cool how it is in the game. Okay I get it you don´t want to have 360° overwatching. But can you at least patch in a button to push so that range and width will be maxed out in an instant (or go back to minimum) so one can just push the button, turn the soldier and hit the „do it“ button? Would make the gameplay much smoother.
Fourth point – Recruiting:
Here I really want to go into X-Com territory. Why not just make it like them? Go to the personal screen, recruit some soldiers and send them to the base desired. Other choices might be recruitment buildings that can be built in the bases where they can be recruited then or build some kind of radio tower so you can recruit them from distant havens to the bases that have that towers built.
Fifth point – Base defense:
So we have a war. We have weapons, troops, factions, mutated beasts everywhere. But mankind is not able to build doors, walls, traps, turrets and hire some militia guards to protect their bases? Why? Why not an extra screen for each base where you can buy (and possibly upgrade) that kind of defense stuff? When there is an attack with soldiers inside make it a manual combat with all defense stuff on the field, if no soldiers are there just let some kind of auto fight decide. So there come 10 aliens and I have 10 turrets, 6 militia guards, some traps, huge walls and doors – most likely the attack will fail and I get some base damage. Cool stuff! The way it is now I can´t say how frustrating it is (even more so considering the fourth point as well) to keep bases protected and defended.
Same should be considered for havens. They should be able to get defenses and use them. At least one might think there should be some guards with weapons. If the Phoenix point project wants to raid them, they have. Where are those guards when the aliens attack?
Sixt point – polish UI and interface:
Just some ideas here. Why no „reload all“ button in the inventory screen so every single weapon (including fury, grenade launcher, etc.) will get reloaed to the maximum?
Also its very hard to find out how to reload vehicle weapons.
Some more icons over enemy heads would be cool. Stuff like „can shoot back“ or „is alerted“ or things like that could be cool information, just with a little icon shown.
Maybe a function to compare weapons/armor/etc. with each other.
Stuff like that 
For now that are the points that I wanted to point out the most. I hope the devs will read an consider those or at least read them. Thanks for that