First of all, I want to express my gratitude for the great experience that I had through the reworked and polished Chapter 1-3. The improvements to the graphical fidelity, color palette, environment, and maps are amazing.
From the beautiful gardens in chapter 1, to the caves in chapter 2 alongside the very good atmosphere throughout that particular act with the chaotic run through the last refuge caves while the worm is attacking the soldiers was quite good.
Chapter 3 was outstanding as we finally get both a rework of the maps alongside an update I was waiting for in beta. That is, the rework of the cultists’ skin and spell palette. Fantastic job. That was a top notch update.
- Though the void thrall looks very outdated in comparaison. I hope there are plan to update this particular skin.
Then we get to Chapter 4.
I felt there was a major drop in quality - specially the swamps area, and the road to tethima, which felt very drab compared to the previous chapters.
I hope personally hope there’s a rework planned for that chapter to bring it on the same level as the previous chapters.
Then there are the void cultists bosses from the void rifts (prophet of ruin and that other one of the desert area) that still have the outdate skins. 
TLDR:
- The void thrall looks very outdated in comparaison. I hope there are plan to update this particular skin.
- Chapter 4 looks outdated in comparaison to chapter 1-3.
- Update prophet of ruins in void rift.