This game has a near-complete lack of headwear and that really makes everyone look same and boring.
Characters in CK2 looked different because each of them wore different headwear with crowns, bands, hoods, military helmets, colourful hats and society tattoos. CK2 characters also wore different things based on rank, for example courtiers would wear the poor-range clothing with simple stuff (character designer clothing range 7 to 11), courtiers in council and unlanded family members would wear the medium-range clothing, and landed nobles and their wives would wear expensive colourful clothes and all the headwear I mentioned.
Meanwhile in Imperator, you'll see maybe 1 guy wearing a band every 50-100 years and no more. Their clothing doesn't change based on rank. They don't even wear helmets. And Roman characters have it the worst - they all either wear Senator togas, or some really bland-looking cuirass if made general. Not a single bit of variety.
The innovation of characters posing in different ways was great, but they still fall far behind static CK2 portraits when they don't have any headwear or much clothing variety.
Simply put, Imperator characters look really bland right now.