I don't see any "Skilled Investigator" class in my PHB. Just an Insight skill which as described is a resource PCs can call on, should they choose to do so.
So, just to be clear... your idea is that it is acceptable for someone to want to play a strong barbarian, an intelligent wizard, or a wise cleric, and have the game mechanically support their ability to do so, but if they want to play a character who is a skilled investigator, you do not feel that is acceptable, and instead is something that should be driven entirely by player skill, with no recourse to character skill?
Again, I suppose there is an approach that style can work for. For myself, I'm not a huge fan of it - just as, if I am playing a thief who is very skilled at finding and disabling traps, it is frustrating when a DM has my character trigger the traps anyway because I didn't describe properly
how I was disabling the traps.
Part of the point of playing a character is that the character can do things that a player, in real life, cannot. One doesn't expect a fighter's player to actually be able to swing a sword or bash through a doorway - or a wizard's player to actually be able to hurl lightning! So the approach of expecting the thief's player to actually be the one figuring out how to disable traps (with no benefit from their character's skills), or an investigator's player to actually be able to tell when the DM is lying (with no benefits from their character's skills)... well, it seems an unbalanced style of play. At least, in my opinion.
That's how reality works, and I don't see anything in the 4e rules to say this little bit of reality should not be applied for game purposes. It doesn't take a skilled liar to have people believe something they already expect to be true, or have no reason to doubt. A skilled liar like a good used car salesman can get people who have every reason to be suspicious to go along with his claim.
Example: Stranger asks me
"Do you have the time?"
I check time - watch says 3.40pm. I reply:
"It's 3.30pm."
Realistically the guy is not going to get an Insight check, active or passive, because he has no grounds to be suspicious. Whereas a policeman investigating a crime, or (most) buyers going to buy a used car, will be using insight, because they are suspicious - yet they can still be deceived.
I... I don't think that is remotely true.
When someone, in real life, actively tries to decieve someone else, there are often all sorts of cues that can give the heads-up that something is off. Now, many folks might be good at, and be able to cover up those elements.
Which we have a way to mechanically represent in the game, in the form of a Bluff check.
The idea that a bumbling idiot can walk up to a group of PCs and tell the exact same lie as a silver-tongued con man, and is
exactly as effective at doing so if the DM doesn't think the PCs have any reason to be suspicious... now
that pretty severely breaks my suspension of disbelief.
Now, I suppose it does depend on what you mean by PCs having reason to be suspicious. You mention that an unskilled liar can still convince PCs of something they have no reason to doubt. But how often does that actually come up?
How often does a PC ask an NPC the time, and the NPC deliberately tell them a slightly different time for little to no reason?
Almost any deception I can see cropping up for the party will often be of much more significance, and I don't see any reason in those situations to simply assume that PCs accept everything as truth, despite some of those PCs being
game-mechanically good at telling when someone is lying to them.
I generally wouldn't require a to-hit check for the PC to hit a helpless, unconscious enemy in a non-combat situation, no. There are plenty of cases where failure is effectively impossible because the action is unopposed.
Well, yes. That's what I said in my very next statement - that there are times and places where you can handwave attack rolls.
But an NPC trying to deceive a PC, and the PC having some chance of detecting it, is not some rare scenario akin to a PC attacking a sleeping foe. It is the social equivalent of a direct combat itself.
Like I said, what are some examples of what you are referring to? If you are truly talking about handwaving bluff checks only in inconsequential or meaningless situations (such as NPCs telling PCs a slightly different time), that's probably fine. But you make it sound like you are applying these rules to pretty much all bluff checks, unless you as the DM decide the PCs have reason to be suspicious and are magnanimous enough to let their PCs' skills be relevant.
Now, this is a decision, as a DM, you have the right to make. You can totally run things this way. But it absolutely is not RAW, nor do I think it accurately resembles reality, nor do I think it is a fair way to handle the skills and abilities a player has invested in their character.
Now, there may still be reasons to choose to run it the way you desire, and there can absolutely be benefits to valuing player skill over character skill. But you should at least acknowledge the truth of what you are doing, and it most definitely is not adhering to the rules themselves, nor is this in any way a more accurate reflection of how deceit works in reality.