On the whole, no. Certain individual feats? Maybe? Theoretically?
Nailed it.
On the whole, no. Certain individual feats? Maybe? Theoretically?
They already answered this question. I answered it as well.
There's no reason you couldn't make an attempt. But making an attempt involves a dice roll to determine the quality of your imitation. Taking the Actor feat means you don't. The feat removes the burden of the player making the attempt, placing the whole burden on the NPC to pierce the deception.
Their players can try almost anything listed in the feats by making some sort of check under appropriate circumstances without the need for rules text to overly mechanize it and, by implication, disallow others from trying those things without that feat.
Slowly, I am starting to see their point. I am starting to think the more rules you have, the less freedom and creativity the player's have under the illusion they have more "options" which were almost always options they had if they could think of it in the situation.
Actor Feat: "You can mimic the speech of another person or the sounds made by other creatures. You must have heard the person speaking, or heard the creature make the sound, for at least 1 minute. A successful Wisdom (Insight) check contested by your Charisma (Deception) check allows a listener to determine that the effect is faked."
Without this feat in the game, why wouldn't you be able to try a Charisma (Deception) check to try and mimic the speech of another person or sound made by other creatures, contested by a Wisdom (Insight) check? And if Player X has this feat in your game, wouldn't it be natural for a DM to tell Player Y they cannot try that because they don't have the feat and it would step on the toes of Player X who spent a precious resource to gain that "ability"?
Inspiring Leader: "You can spend 10 minutes inspiring your companions, shoring up their resolve to fight. When you do so, choose up to six friendly creatures (which can include yourself) within 30 feet o f you who can see or hear you and who can understand you. Each creature can gain temporary hit points equal to your level + your Charisma modifier. A creature can’t gain temporary hit points from this feat again until it has finished a short or long rest."
Without this feat in the game, if a Player makes a very inspiring speech which the DM judges would give a psychological boost to their allies, the DM might choose to give those allies some temporary hit points from the speech related to the PC's charisma (and probably would limit it to those who could hear it rather than an arbitrary 30' distance). They might even allow it a second time without as rest, under appropriate circumstances (like a forced march while chasing foes who have kidnapped their companion). But with this feat in the game if Player X has it, it would be hard for a DM to justify allowing Player Y to try it, or to even alter the rules to have it work without a short rest or outside 30' because the rule is right there in black and white on a PC's character sheet that way.
Keen Mind: "You always know which way is north. You always know the number of hours left before the next sunrise or sunset. You can accurately recall anything you have seen or heard within the past month."
Without this feat in the game, any of these things could be determined with an appropriate ability/skill check, or perhaps even automatically depending on the circumstances. And maybe it still could even with this feat in the game. However, if Player X happens to have this feat? The DM will probably naturally feel more reluctant to hand out that sort of information without the feat to the other PCs who lack it.
Linguist: "You can ably create written ciphers. Others can’t decipher a code you create unless you teach them, they succeed on an Intelligence check (DC equal to your Intelligence score + your proficiency bonus), or they use magic to decipher it."
Without this feat in the game, I see no reason why any PC couldn't try and create a written cipher which could be broken by an Intelligence check similar to the one described. With it, I can see a DM having trouble justifying allowing such a thing without the feat.
Mounted Combat: "You can force an attack targeted at your mount to target you instead."
Without this feat in the game, I cam definitely see circumstances where a player will argue they can intervene in a strike against their mount like that. With it...DMs will feel the pressure to not allow that if some other player has the feat and they don't.
Skulker: "When you are hidden from a creature and miss it with a ranged weapon attack, making the attack doesn't reveal your position."
Without this feat in the game, I can see a Player reasonably trying to not reveal their position after a missed arrow attack, depending on the circumstances. With the feat, DMs won't want to allow that if another PC has the feat and you don't.