Correct me if I'm wrong. You're stating that some NPCs are not going to be easily intimidated. I agree 100%. In my campaign the PCs fight everything from cowardly goblins to professional soldiers that are much tougher than the typical town guard soldiers. The goblins can be intimidated, by and large the soldiers cannot (it's not always quite that simple of course).
The reason I don't like the menacing feat is because if you just take the feat as written, there is no wiggle room in who can be intimidated as long as they are humanoid or what the results will be. Win an intimidate check and the target is frightened. Frightened has a very specific mechanical in game effect unless they are immune to fear.
You can always add to the feat "if the DM allows a check", but it's not what the feat says.
Some of my players are "rules lawyers"* and would be upset if I say "no because I said so". I don't understand why that is a hard concept to grasp that I would rather not upset my players.
*I'm not a rules lawyer, that doesn't mean I don't respect their opinions or point of view.
Sorry to belabor a point here, but, how is this any different from what we had before the feat. You mentioned earlier that a successful intimidate check would have "some" benefit. What exactly does that mean?
Ignoring the feat for a minute, what would happen if my PC successfully intimidates an NPC in combat? What would you actually do? How would you rule?
OK until you have an 11th level rogue with a high charisma and reliable talent and their minimum check is higher than the target can get with a die roll of 20.
Again, we've had this in the game since Day 1 and it hasn't been a problem. Or, if it is, nobody is talking about it. And, again, if my high Cha rogue with reliable talent and expertise in Persuasion talks to your NPC and succeeds, what does that mean? Is it possible that I talk the NPC out of attacking me? Can I stand in front of a hostile NPC, convince it to talk to me, talk to it and make a successful persuasion check and it still eats me?
And you're worried about these feats pissing off your players?
So, Oofta, I'm going to ask again. Because you've brushed it off twice already. What would you actually rule that these skills do when used successfully? What does a successful Intimidate check mean to you? What does a successful Persuasion check mean?
Because, AFAIC, the effects from these feats are perfectly in line with successful checks.