Introduction: Hello, i hope you can read this whole think i just worte in one go and hopefully that helps you, i mean everything to be constructive feedback, please take no offense, english is not my primary language too.
Boss in the crucible: The boss in the crucible became a sponge, bosses should have longer stun periods and/or mechanics that lead to a window of time where you can deal tons of damage and then start to read mechanics again, legendaries are really bad.
Game focus: You should focus on single player and story first because that is top class, meanwhile change the combat/ effects/ stats design Increase the high risk high reward mechanics and make everythink work based on damage dealt and taken, just quit that % and hit thing that is bugging averythink out.
General combat design: Imho the design of effects and stats based on number of hits and % is killing the combat experience. Atm we just need a couple of effects and can spam skills doing tons of damage perma stunning everything while healing. Ranged felt super cheap and easy with the locking on enemies from so far away and ability spam.
Skills Design: Add skills that are more than a spin or jump and hit, give them a cooldown other than a focus requirement/consumption and balance the game based on that (just look at mmos or mobas and take inspiration from there, can have shields, fear, silences, grabs, disarms, sleep, polymorphs, reflection of projectiles, energy beams, turrets, magic orbs, healing auras, elemental forms like fire that make you intangible and can walk through enemies setting them on fire, or water to wet them and then combo with electricity, shadow to posses enemies at execution trashold to walk them in a group and make everythink explode, ice to create a slow aura or barriers in form of 1 hittable walls, stone skin, stealth, dashes that displace enemies and stun on wall collision, marking enemies to teleport on them, tricks to lure enemies in a different direction with thinks like summoning illusions, trowing items on the ground… taunts and so on).
Weapons stats requirement: The stats requirement to use a weapon is old news tbh, all weapons should be used in their normal state and we should have increasing benefits for having a higher amount of the correct stats and not be punished for not having a base requirement (benefits like, cooldown and focus cost reductio, higher damage, higher effect duration, movement speed for 2 sec after using a skill, damage absorption after using a skill, guaranteed crit after using 2 skills etc etc and maybe a special skin/icon image and weapon visual effect for maxing out the correct stats).
Healing and resources management: Insert a flask system and make the current recipes become a power up to flasks, early game is stressfull to go around gathering herbs just to heal a bit while knowing nothink: resources position, game mechanics etc… is just a burden too heavy to carry. Also reduce the amount of different resources gatherable or make all recipes use all tier of materials or even better make recipes upgradable and craft them using all tiers of materials in different amounts or we will have tons of useless materials and recipes after a week of playtime: assign every material a value of contribution to a recipe, for example T1 mats contribute 1 point so you need 1xT1 mat to complete a 1xT1 recipe, when you upgrade to a T2 recipe you then use 2xT1 mats to craft 1xT2 recipe or 1xT2 mat, this way you thin out the menues and ease players life, oc T3 and T4 will need multiple of 4-6-8 times the T1 mats but this way all the zones resources stay valuable, you just balance that how u want.
Buffs: You should split bufs and hp recover items and make buffs not share cooldown with eachother, makes no sense to wait 4 min to start a fight with buffs, make buffs time duration of the same type and tier stack, example a +10 strenght that lasts 10 minutes should be stackable to 20-30-40 minutes…
Character investment: To invest in a character and “make every choice matter” is old news too, new players dont know what they are doing, casuals will never know, metaplayers will copypaste the unbalanced build of the week. So design based on that, we play mobas, mmos, class shooters, fighting game where you can switch and play all type of characters, builds and tactics every 20 minutes, you need to understand that, you need a dynamic and modern game or people will end up with tons of weapons and armors in their chests having nothing to try and have fun with for days just because they need a + 5 int to use a shield but they dont want to commit points because dont know the game, people will get bored and quit.
Conclusion: Point is that you need to keep the depth but refine the complexity, so players can experiment, adapt their playstyle to the situation and benefit from everything you crafted.