My feedback after going through all the content

Hi. I have over 5k hours in PoE 1. Here, only 320, but I have already familiarized myself with all aspects of the game and I will share my observations. I don't know if the opinion of a no-name like me matters, but I hope so :)

Leveling process
This is the best thing that has happened to me in recent years in MMO/coop games. Playing the campaign with friends is fun. The ability to revive each other makes it easier to complete the campaign and gives a lot of interesting unforgettable moments when, for example, everyone is dead and the last friend saves the day for the whole team. However, I think the bosses have too much hp in big party.

Gear
Gear upgrades are weird. The higher the item level on rare items, the higher the values ​​on the individual modifiers. However, I can't have two or three really good stats at a high tier. I didn't feel this problem in PoE1.
Unfortunately, +levels to gems have too much importance. Even if an item has good stats but doesn't have +x levels to gems, it has practically no value. In my opinion you should reduce this significantly or remove this modifier.

Rarity on items should work like in PoE1, because not having a lot of rarity means losing a lot of real earnings. Currency should not depend on this.

Unique items, on the other hand, are too weak. Most of them have no market value. In PoE1 unique items are divided into leveling uniques and endgame uniques. There are only a few endgame uniques in this game. Most builds are based on the same items like Astramentis, Ingenuity or Hand of Wisdom and Action. They are too versatile and fit most builds.

Passive Skilltree
I like the distribution of passives on the skill tree. However, I don't understand why you gave up on increased maximal life, and left modifiers for mana and energy shield. Because of that almost no one plays for life and it is only a stat needed to stack spirit/ES for summoners. If someone has to play with HP, they usually also play MoM.

Endgame

Atlas Passive Skilltree
Atlas talents are very weak. They don't do much. What's more, I don't like the fact that everyone can max everything and play every content on maximum settings. Instead of focusing on one or two main things, you can play everything and benefit from all the upgrades. This is a bit too easy a way to increase currency earnings.

Atlas Map
Unfortunately this is currently the worst part of the game. Nothing is intuitive here. Everything is on top of each other. It's hard to find a map with a specific modifier or a citadel. There is no search bar. You should add a minimap like delve in PoE1. Biomes can change every two maps, which causes a complete loss of immersion. Wraeclast is not how I imagined it, as endless boring areas repeated over and over. I like the atlas from PoE1 much better, where I can farm the maps I like.
If you're going to stick with the current solution, at least separate the biomes attached to citadels, so that the maps that appear in them can be found more often than just in citadels.

Pinnacle and Endgame Bosses
The Arbiter is a well-designed boss, although playing him with multiple people is pointless if the party doesn't have enough DPS to oneshot him. Bodyblock is the main problem here. My friends died during the phase of entering fields because we blocked each other. As a result - you should remove the bodyblock for friendly units. Nobody needs it.
King of the Mists and the boss on breachstone (I don't remember the name) have interesting mechanics and I had fun doing them with my friends.
Simulacrum gives very few rewards, is very easy to do, and requires too much effort to craft it.

Overall conclusion
It's still early access and there will definitely be a lot of content. It's great that many things are changing for the better. Unfortunately, one of the first major patches completely disabled my blood witch build, which meant I had to make a new character. You should balance such things with the new future league.

Don't forget about PoE1. Many people at my friends' (including me) are waiting for new content. You promised that you will release leagues alternately for both games. Please keep your word :)

I keep my fingers crossed for the project and am waiting for new patches.