OK this is going to be a long post, so get ready.
I like the new rules. I don't think it's too much of a pain for a rogue to have to be completely concealed or hidden to be able to stealth. This does nerf ranged rogues a little bit, but not a huge amount.
However, what I don't like is now I need to be very aware of how superior cover works vs. normal cover, and how someone can achieve superior cover. Previously, I basically just said cover is usually normal cover unless they are really blocked, by like an arrow slit. Now that rogues need to be aware of how to work Superior Cover, I sat down and drew up a couple scenarios, and found that I don't like how D&D handles it at all. For example:
In the diagram above, Troll B has superior cover from Hero, while Troll A only has normal cover. But it's quite obvious that more of Troll B is visible to Hero. Because of the ruling that lines along a wall or corner don't get blocked, Troll A is easier to hit than Troll B.
The same goes for Elf B. Elf B has normal cover, being on the exact opposite side of a pillar. Elf A though has superior cover, because only one corner is available from each corner of Hero.
This to me means that a rogue who wants to get superior cover to hide has to be very knowledgeable about how the GAME TERMS define superior cover, rather than thinking "Oh, I want to hide behind this wall." In a non-diagonal situation such as Hero->Troll A above, there is in fact NO WAY that Troll A can get full cover unless they step back away from the corner they are up against. That means they can only stealth once every 2 rounds, while Troll B can stealth every round, simply because he is on a diagonal.
I don't mind that a rogue can only get CA every other round if they do it ranged. That's perfectly fine with me. But I don't like that if you set yourself up arbitrarily based on how the game works, you CAN get it every round, if you are able to work on a diagonal.
I have a proposed solution, and I'd like your guys' input on it. (This is obviously a home rule sort of thing, but I think it fits here in the discussion of the new stealth rules pretty well)
I propose that the rules for cover be changed to this:
A defender has normal cover if a line from one of the attacker's corners can reach 1-3 of the defender's corners, no cover if a line can be drawn to all 4 corners, and (obviously) superior cover if a line cannot be drawn to any corner.
However, a defender may spend a minor action to "press" against cover. This gives them superior cover against anyone who they previous only had normal cover against. Stealth can not be used as a part of this minor action (because stealth is now a part of a move action only). Superior cover achieved in this way is lost after any other action is resolved.
What this means is that in most combat situations, people will only have "normal cover" or "no cover". If they have normal cover, they can spend a minor action to get superior cover, but if they pop out to attack, or if they cast a spell, or do anything else, then it just becomes normal cover again. Because the cover is removed AFTER the action, you can use a move action to make a stealth check after using a minor to "press" against normal cover to become stealthed.
This means that yes, a rogue CAN get Combat Advantage every turn, by doing the following:
1. Standard Action: Attack from cover. If previously stealthed, attack with CA.
2. Minor Action: Press against cover to get superior cover.
3. Move Action: Stealth, lose superior cover but gain stealth.
4. Repeat steps 1-3 as desired.
However, this takes ALL of their actions, and prevents them from moving if they want to keep the cycle up (unless of course they are moving such that they would keep Superior Cover through other methods, by being completely blocked from view or whatever else), so it may not always be the best course of action.
This also works if someone is standing behind a low wall. Use a minor to "hunker down" to get superior cover, a move to stealth, then a standard to pop up and attack, losing stealth.
It sounds complicated but really it's just a way for people to do what you always see "in the movies", and that is to really take advantage of cover in a pro-active way, rather than drawing lines every round to get crazy technical and worrying so much about positioning. I think this is a nice middle ground between the previous stealth rules (pretty much stealth every round) and the new stealth rules (stealth every other round, or every round if you're lucky enough to be on a diagonal). Now it's stealth every round if you give up everything else, no matter what type of cover you are behind, so it's no longer an automatic thing anymore.
And because it's action-based, someone could always use a readied action to attack "when that rogue pops out" so that they attack against them with standard cover rather than superior or whatever else.
I know it was long, but I think it's pretty balanced and fair, I just don't like how cover and superior cover currently work, so please let me know what you guys think.