Through my countless hours of playing I have also thought a lot about the game and its mechanics and ways that you could improve the playtime and quality for your players. Of the many points that could be said there are 3 major improvements that could substantially boost the value and playtime for players like me. Firstly it is the subject of armor classes. Currently we have 4 main classes of armor: Cloth, Leather, Mesh and Plate with no distinction between classes besides weight, armor and poise value. Furthermore, the sets within each class, although visually different, are identical to each other. By adding distinctive perks to each class and set, that works towards certain builds, you will be able to improve the gameplay experience for players who seek to maximize their builds. For example cloth could boost magic damage, leather could boost dexterity and so on. And each could have either a bonus for full set or each piece could have a distinct boost to a certain stat. This change would help create more efficient classes like mage, rouge, warrior and tank.
Secondly, although I have no played the Breach, staffs and wands could have normal ranged attacks like the bow that would help the player with focus regeneration. Currently focus regen is either too strong or non-existent. Having to walk up and melee with a magic staff breaks the ranged-mage style of play and is counter-intuitive.
And lastly, I know you’ve mentioned that the unique weapons need improvements. Right now, there is no unique weapon that is better than a legendary and no-one uses them. One quick fix would be to allow these weapons to have their runes extracted and replaced without destroying the weapon itself. I know this may be an overpowered mechanic, but one worth trying while in early access.