I’d like to see a way to change the upgrades whether it be a personnel upgrade or a squad upgrade. It seems to require an item that is fairly difficult to acquire as I have put in a lot of time playing the game recently and without the battle pass and don’t have it nor do I think I was close. I don’t think I should have to pay for the mistake of choosing the wrong perk. I don’t really like that whole concept and I honestly would prefer if there were a way to temporarily change your upgrades how you want to and change them back if you don’t like it for free. Other games have reset perk options but this one requires a rare item or money. I would also like to say that I like the new battle pass and I bought it to make things easier on progressing because man is it time consuming to level up. I like the way the game is set up overall and there are issues but at least they take feedback from people and don’t pretend to. I am also gonna say the campaign levels are quite difficult to progress. It requires a grind to get to a point of enjoyment at least for a little bit. I feel like time to level up should be reduced because of the games where you only get a few thousand xp when at the point I’m at the next level is over a hundred thousand xp away. Something else important to me on my mind right now is the star progression rate of individual soldiers. Some of the different kinds of squads can be difficult to level up soldiers which you have to do if you don’t want your reserve full which would prevent you from being able to unlock new troops to use. The squads I’m referring to would be mortar man and the radio squad which I find particularly difficult. I also was gonna include tankers and pilots but I’m not good enough to take either of those seriously or I don’t have the right armaments I’m not sure. There is just a ton of them sitting in my reserve waiting to be leveled up and I end up dismissing them to make room for things I’m lacking in. Enough of my rambling let me know your thoughts.
This is hard. If you reduce the XP needed to the next level you could have everything too fast and you will lost the feeling of progress.
Perks or squad upgrades never bothered me. They are not that important. If you used bad one, after few hours you will have another squad or soldier and it won´t matter anymore.
XP in general depends on your skill. If you are good and you get first place of your team or get awards, XP will grow fairly fast. I have only small problem with XP for squads, in every game you can get first level easily and the bigger lever you have the harder is get another one. But this game has opposite approach - first levels are hard and next are more and more easy. Today i played with new tanker squad, a kill 70 soldiers, i was the first from my team a get tanker and vehicle award and get approx 25% XP from level 2 
in conquest maps it will take forever.
It will be good for you to focus on leveling only few squads. Don´t spend all your orders as soon as you get them. And train soldiers in academy. I personally do not like flamethrower, planes and mortar, so i move all those soldiers i got from random orders to the rear. And i neved had a problem with full reserves. Maybe consider if you need the pilots with hight level - do they realy need it?
I regularly delete all the 1-star new soldiers from unwanted classes - fighter pilots, bombers, etc.
Once you get up a bit you start receiving 2- and 3-star reserves on a regular basis and the 1 star ones are just a waste of space.
Likewise indeed. Lvl 1s just take up to much space and require so much switching. You get enough 2+ to have the academy going non stop