Flavor Text
Good
iserith " I slowly look over the altar with my magnifying glass, knock three times on each blue gem, and spray silly string around the base looking for traps"
Rolls 3 adds 8 missing the DC
Bad
Iserith, " I lick my eyebrows. Wink at the Princess and say do you want to BEEP!"
Rolls 19 subtracts 1 passing the DC.
DM response
Good, " Your hand press down on a ivory rose causing the trap to trigger. Take 11 pts"
Bad, "groan. groan. Ok The Princess declines your off to BEEP but she is amused. You and one other of the group get a war horse upgrade for the quest.".
Some people are good at flavor text some you just groan when they open their mouths. While it is in the DM power to change the dc in favor of the good flavor text person, he should not. Why? Because Jasper can't flavor text to save his life.
I think this is just where different people do it differently. In this regard, D&D seems to straddle and support two approaches. Neither of which are wrong, just different.
What you are describing sounds like players, when faced with a situation, push a button on their character sheet. They then "flavor" that button push with some description, and the DM flavors the success or failure (based on a die roll and a pre-established DC) appropriately. I think there are tabletop RPGs that exist firmly in this camp — player actions are explicitly bounded by certain moves or abilities.
My goal when playing D&D is to have the player actions not be bounded by the buttons on their character sheet. The "flavor" as you describe is the thing. The skills on the character sheet are how we resolve the thing, if necessary, but the resolution of those skills will determined by the actual thing the players are describing. Does the character move through the room, rooting through piles of clothes, sticking their head under the bed, rooting through drawers? Or do they stand in the center of the room and try to apply Sherlock Holmesian deductive reasoning to spot faded footprints, fallen bits of ash, places where the side of the bed looks to be worn, or what have you? The former is going to be an easy check (or probably not a check at all), but might have consequences. (There is a grue under the bed. There is a giant centipede in the pile of clothes. Opening the dresser makes a loud creaking noise.) The latter would be a nearly impossible feat of Investigation, but might be possible for a Rogue with Expertise.
This approach should not be about punishing players who are less articulate than other players, or players who are unable to describe their actions in paragraph length prose. Most character actions can still be described in a simple sentence or two. I don't need to know that the player knows how to disarm a trap, or knows how to win an argument with a goblin about politics. I just need to know what the character is doing and what they are trying to accomplish. This approach
does reward players who are imaginative and who are paying attention. I think that's ok. D&D is a game, and all approaches are going to reward something.
----EDITED TO ADD-----
For instance, if a PC crudely propositioned a princess, that roll would probably be to keep from getting their ass beat by a guard, thrown out onto the street face-first in the mud, or dragged into a dungeon.
PLAYER: I crudely proposition the princess.
DM: Umm, ok, give me a roll for Persuasion.
PLAYER: 19. -1. So that's an 18.
DM: The Princess smiles coldly. "You must be confused. I'm going to give you one more chance to tell me why you're here, or I will personally haul you by the ear to the edge of this town and throw you to the bears."
