I struggle with the following :
You enter the room and a dark, old man dressed with a humble and threadbare mantle is prattling in a corner. When he sees you, he stands up and comes forward, smiling sincerely. His face has sharp contours and his eyes express the resolution and vision of a true leader
The NPC has successfully made a positive impression on my group. I described the NPC as their characters saw him.
On the opposite :
You enter the room and a old skanky man, with a ragged robe, is talking under his breath from a corner. When he sets his piercing eyes on you, he stands up and comes forward, smiling too widely. His sharp face looks almost cruel and his eyes seems to look at everything as his to claim
Well, if they don't all pull their swords after this and raise a shield, they deserve their incoming death, right ? jk, I hope you understand what I tried.
I tried to describe the same person from 2 different perspectives (I am not an English native speaker, very sorry if I failed to explain my issue).
First description: poor nice old man, maybe a previous village leader or a current wise from a poor community, babbling memories or old folks song.
Second description : austere old man, might have set up a spell, focused only on power and driven by ambition. (I am a bit better in French, I promise).
My group has a paladin that detects evil aura (automatically, all day long right ?). Some of the group have terribly low wisdom. Others have great stats and can detect bluff and stuff. Thus, they should not see people and things the same way. I struggle to deliver consistently interesting interactions with my universe NPC (and places).
If I describe what each one sees, the group can just rely on the paladin or the druid to see the world. Descriptions become useless and I am condemned to use a neutral align NPC (which works from time to time but it is less sexy than an evil eminence grise, proxy of their archennemy) if I want to add elements of surprise or doubt.
How to deliver interesting descriptions opposed to 'it's an evil mage at least level 7, usual evil mage stuff'
I describe what every one sees, player's job is to roleplay their character. But it feels constrained and a bit false when they know their character is deceived. And the group ends up taking the good decision.
I describe what the most perspicacious one sees because, anyway, the group follows his recommendations on these points. After all, it is why you create a balance group, to get all the skill on the table.
I create an average perception for the group, factoring the characters' abilities and external factor (shared races, known background...) and roll a dice. The group shares the perception. But the streetwise characters's players might get frustrated.