It is. You are only using the distracted enemy example.
Because it's by far the most reasonable assumption.
Let's say the enemy is not distracted (vigilant city guard).
Let's say they don't have superior cover or total concealment, but have partial concealment (twilight).
Then, around the corner or in a buildings doorway or similar they hide. They then move through the city with the partial concealment - even with the rest of the party. He can then walk with the party completely normally after that due to the twilight. Unless these city guard are literally omnipresent and everywhere, this is a pretty moot issue (and if they are, then you're not having an easy time sneaking in the first place).
So your example fails immediately on that point.
Let's say they are directly in the enemy's line of sight (walking down the road towards the gate).
Let's say the party is making no attempt to hide.
The Shade can hide from the guard in these conditions, outside of combat.
So can a regular rogue who is trained in other skills. Also I dispute that the shade can hide, because allies as cover is actually quite dubious. What is the parties formation and what is the line of sight of the guards? Can no guards draw a straight line through to the shade PC without touching another PC (and that's the definition of cover from a PC). Also, both the shade and cunning sneak in your scenario do not require their allies, because they can hide using the concealment alone. Other characters can use items that dim lighting, utility powers or just their regular powers to make a stealth check to become hidden.
So the shade is at no special advantage whatsoever still.
The guard could be watching him walk down the road towards the gate in the dim twilight and he can just disappear and walk right past the guard
The allies are irrelevant, because he can do so with concealment and the cunning sneak can do this as well. So can many other characters trained in stealth, such as the warlock whose shadow step will provide concealment, stacking with the current concealment to provide total concealment for him to hide.
You've manufactured in detail a scenario that the shade is no better at than the cunning sneak (and many other classes).
It isn't hard for a player to let the DM know he's going to move to keep his allies between him and the guard in an out of combat scenario
Depends on where the guards are and this isn't as easy as you think: Medium creatures don't block LoS easily and it takes one clear LoS to break hidden. That's it. In the scenario you made though it's rather irrelevant, anyone trained in stealth could (when no guards were around) hide and follow his allies. The concealment you've provided means that the town guard won't see them unless they beat his stealth check.
and a ready action would easily let someone do it in my game in-combat)
Okay, so that seems fine. Can you explain to me where the shade is getting the standard action to ready to do this from? Considering he needs a standard action to use his racial to use an ally as cover to begin with - where is the standard action coming from to ready the action? What exactly is the shade going to do all combat? Occupy a square?
The non-Shade (non-Cunning Sneak) cannot hide from the guard in these conditions, without a distraction, gaining superior cover or total concealment, or going outside of the guard's line of sight.
All of these are easy enough to actually do with roleplaying, items, feats and utility powers. That's the entire fatal flaw to this supporting argument. These are things the character would be taking anyway as well.
The guard would be watching him walk down the road, and he'd either need to duck off the road
May I ask, would there be a particular reason he couldn't have been using stealth from the moment they left their inn or similar in the first place? I'm confused as to your example, because you're trying massively hard to make something in the shades favor and yet I can't quite see how this is supposed to be something the shade can only do. If the place is in twilight (concealment everywhere outside) when they leave, if there are no guards they can hide in the first place. If the guards don't have a reason to be looking for the PCs, why is getting out of sight to stealth a problem? If the town guards are hostile for the character trying to stealth, why isn't he doing that to begin with anyway?
Let's say the enemy is not distracted (vigilant city guard).
Let's say that the area is a brightly lit hallway, at least 3 squares across.
Let's say the guard is positioned to 1 side of the hallway, at the middle of its length.
Let's say there is no concealment and no cover aside from an ally.
Let's say the ally is making no attempt to hide.
The Shade can hide from the guard in these conditions, outside of combat.
It just took an immense amount of absolutely, 100% completely specific engineering to make this. However, let me just say that if you can generate concealment this is now entirely irrelevant. For example a warlock see the guard, he stealths outside of the guards line of sight and then waltz down the hallway with concealment.
He doesn't need his allies and neither will they give him away.
He does this by a class feature he's granted for free, that costs him no action to use.
He makes his own concealment, so staying hidden is no problem.
Incidentally, I do wonder why the allies are wandering down the hallway not giving the entire game away. I mean if you're trying to be stealthy needing three allies to march down the hallway in plain sight is the most ridiculous thing I have ever heard of.
Unless the guard has some reason to actively look for a dude hiding in the shadow of a guy walking openly down a hallway, it'll go off without a hitch.
I can think of so many logical problems with your argument here, beginning with the fact the guard might wonder "Why are three heavily armed random individuals walking towards me?"
You are hidden, but your allies aren't and if the guard doesn't react well to that your entire strategy breaks down like a house of cards. Say you can only go halfway down before the guard tells you that if you go any further that the jig is up. Now your allies can't go anywhere and the shade is no better off.
Effectively you need to engineer such a
highly specific set of circumstances for this to be useful, that you actually make my argument for me.
The non-Shade (non-Cunning Sneak) cannot, since he cannot use his ally as cover and the guard is not distracted.
Yet if he has a source of concealment he almost certainly can - this is not hard to do with items.
I said that the trained PC cannot begin to hide without superior cover or total concealment
Which are just about stepping out of line of sight, with distracted enemies they don't actually need either (if you noted). I again, would like to point you towards the out of combat stealth rules, where you require neither total concealment or total cover to begin hiding if the enemies are distracted.
I've had a Cunning Sneak in my group that has been able to use his group to keep himself hidden from enemies quite well, despite my efforts to break the cover granted by his allies.
Without another power, a cunning sneak cannot use his allies as cover to become hidden.
Cunning Sneak said:
If you end your movement at least 3 squares away from your starting position, you can make a Stealth check to become hidden if you have any concealment or any cover, except for cover provided by intervening allies.
I do recall that a power can do this though, but you can't ordinarily use your allies as cover to remain hidden. Also allies do not provide cover to remain hidden.
Stealth Rules said:
If you no longer have any cover or concealment against an enemy, you don’t remain hidden from that enemy. You don’t need superior cover, total concealment, or to stay outside line of sight, but you do need some degree of cover or concealment to remain hidden. You can’t use another creature as cover to remain hidden.
Unless the cunning sneak in your party has a power or item that lets him use allies to remain hidden (and as cover for a stealth check), he's never been able to do that to begin with :O
I never said this is better than Cunning Sneak. Let's stick with things I said, like the fact that it is better than someone simply trained in Stealth.
My point there is the opportunity cost involved - especially in actions. The CS just does this. The shade pays a standard action and a -1 penalty to surges. Anyone else has a slightly, but not overall more arduous time doing it.
...and they can use partial cover and partial concealment to begin hiding, which is a big advantage when lighting conditions are actually defined.
So? What point does this have to anything I've said? The ordinary guy trained in stealth can begin hiding before combat and remain that way in the same lightning conditions. The shade can be more reactive - that's true - but a canny player can realize his disadvantages and start hiding before he's ever in trouble.
It hasn't been hard for my group's Cunning Sneak. He has managed to enter towns with his picture posted at the gate with the group because he can hide behind any of them
Unless he has a power or a feat that lets him do this, no, no he actually can't. Cunning sneak specifically rules out allies and the stealth rules specifically rule out using allies as cover to remain hidden.