Sorry, I thought i had laid it out, let me try again.
-They replace things like keen senses with a bonus to perception in the statblock.
-Dms may not be aware why the perception is higher.
-DMs that would have noticed keen senses don't play the creature as if it had a special ability.
-If the wording in the lore retains a keen senses description, all is well.
-If the wording in the lore doesn't mention any such trait, then it is lost and no longer a part of that creature.
Therefore I hope all these mechanical simplications don't make traits inherent to the creature "disappear"