Paul Strack
First Post
I do like the concept, but I'm a little worried that it's maybe too easy to achieve - all you need is a little bit of cover/concealment, since you're not worried about being found afterwards; and your check is never opposed by an active Perception check because its effect resolves immediately rather than on an opponent's turn. Then again, maybe it really is meant to be that easy.
I am convinced that getting CA from Stealth is that easy. The fire-and-forget Stealth is clearly allowed by the RAW. I don't think it's game breaking either. For most characters, it's just a +2 bonus to hit. For Rogues, it makes their ranged damage output comparable to Rangers (the better Sneak Attack bonus is balanced by more restricted weapon choices).
My personal house rule is that this kind of "insta-stealth" is a Trained Only option, mainly to stop everyone from doing it.
For your lasting Hidden condition, require a move action that takes you through or into cover/concealment, and rule that you become hidden only at the end of that action, so the enemy knows which square you hid in. The only way you can prevent them knowing which square you're in is to spend another action moving through cover/concealment once you're hidden.
That's pretty close to RAW, and it gives you your two levels of stealth - an instantaneous condition as part of an attack, and a lasting condition that requires two move actions to take full advantage of.
The tricky bit with a lasting hidden condition is that you can be hidden from some enemies but not others. Who you are hidden from can change quite a bit over a round. What I was originally hoping for was a simple on/off hidden status that applied to all enemies. The arguments above convinced me that for consistency with the RAW, I have to accept hidden-from-some-but-not-all as a possibility.
It makes things more complicated to adjudicate, but I think I have an inkling of how to manage it without being too tedious. In particular, when you hide, you roll to establish a "Stealth result". You are theoretically hidden from everyone whose Perception you beat, but you don't have to actually compare numbers it until they try to attack you.
Later in the turn, if an enemy decides to attack you, he can so freely if (a) he has a clear LOS or (b) his passive Perception is higher than your Stealth result (meaning your original Stealth check failed against him). If neither of those conditions are true, you are hidden from him and he has to follow TWYCS to attack you. People have suggested similar rules in other threads.
There are a couple corner-cases that don't quite work right, mainly having to do with enemies gaining and then losing LOS during a turn, but it is close enough to RAW that I could work with it. I am going to mull it over and see if I can turn it into a straightforward, near-RAW house rule (By "near-RAW", I mean close in effect to the RAW, not literally RAW).