I have been on the grind since I've gotten the game and have already gotten all of the items and gatekeepers. Looking at items as well as playing with different gatekeepers I started to form bias towards some over others
An example that I'd show bias towards is the Tarra's Claw and the Opal Eye. Both items have a pretty decent dmg % increase of 25. However the Tarra's Claw feels like a downgraded version of the Opal Eye as it only works on bosses where as the Opal Eye works on all enemies. The solution may be to nerf the Opal Eye or buff the Tarra's Claw. This will hopefully add more variety in the items that players choose rather than just forging one for the other.
In the most recent hotfix that changed the ability of Hybrid and added a 50% dmg boost after the first death, it made Nidum's ability seem worse in comparison. With both of the characters being starter characters that you have already unlocked, with the change Nidum's ability just seems far worse in comparison. Now the maximum damage boost of Nidum being 50% sometimes and Hybrid's boost of 50% after a revive just lowers my incentive to play Nidum.
This last point may just be me complaining about myself being bad or unlucky but the Mediator (keep in mind I haven't played him since the hotfix) seems almost too frail. Most of the time when I try to play as Mediator I am finding it very difficult to last past the first boss. Other than the very obviously low health, some of his abilities don't feel strong enough to hold their own. Against single target enemies like a boss his damage is rather low if I can even get there due to a pillar event killing me during the charge. This compiled with his ability being very situational makes it feel like a good run is dependent on if you are lucky with artifacts and getting a good curse shrine.
This is all from my perspective and it's understandable if others don't feel the same way. Hopefully this post may provide insight for future development.