If you are confused about what I talk about with skills, you can see http://www.gamesas.com/index.php?/topic/1316071-how-i-think-a-complex-rpg-oriented-skill-system-should-be-implemented-in-tes-games/ for reference.

Now, here are your stealth skills and subskills.

Sneak
The first subskill (not properly named yet) is avoiding detection. This determines how quietly you move, how easily NPCs can see you, and how fast they will lose track of you when you hide. The second subskill is sneak attacks, such as backstabs, how much damage they do, and the chances of doing one succesfully. As a low level sneak player, this will have a chance of failure if done with melee weapons, in which case the enemy notices you, blocks your attack or you do normal damage as they attempt to avoid it. Aside from this, sneak will work similarly to Skyrim, except that enemies will start actively searching for you when their friends are killed.

Security (Or "mechanisms"
The first subskill is lockpicking. The minigame will work similarly to Skyrim except it is more character skill based. It will be impossible to complete expert and up locks from the start, these will be progressively unlocked. You can also lock doors using a similar mechanism. The major difference will be that lockpicking is in real time, and if someone sees you doing it, you get a bounty. They will also have a chance of hearing you and coming to investigate, a chance that will reduce as you raise your level in it. The second subskill will be trap related mechanics. I'm not entirely sure what sort of traps, but you will be able to set up and disable certain traps such as pressure pads.

Guile (Or "speechcraft")
The first subskill is persuasion, which will be closer to speechcraft in Oblivion than Skyrim, in that there will be SOME sort of minigame, having a static "persuade" button is very uninvolving. It will be different to the OB one, though, and much more character skill based. The second is essentially mercantile as seen in Oblivion, though I'd be happy to hear suggestions on how it could be made somewhat interactive.

Acrobatics
The first subskill is climbing (Yay!) which will allow you greater ability to grab on to and hoist yourself on to ledges, vault over fences, possibly scale certain walls, do small wall runs, pull yourself up ropes etc. As you level, you will get faster, and more climbing abilities will be unlocked (probably either through optional or preset perks). The second subskill is dodging and rolling, which basically gives you the ability to perform sidesteps, backsteps, backpedal faster and dodgeroll, as you progress, and with progressive speed. The final subskill, like acrobatics in Oblivion, determines the height and distance of your jumps, as well as how easily you take damage from falling.

Theivery
The first subskill is pickpocketing, which will work similarly to pickpocket in Skyrim, except with the additional style of pickpocketing in large crowds by walking stealthily, which can be activated like sneak mode and put you in a mode of "casual detection" where the NPC is less likely to notice you stealing, particularly in groups. The second subskill will deal with taking items. You will no longer be able to take any item out of sight. Now, NPCs will be able to "hear" you stealing heavier items or opening chests from the next room and will come and investigate, and have a chance of noticing what you have taken. This can sometimes even awaken sleeping NPCs. As you level, they will be less likely to detect this, and at a point, you will be able to use the afformentioned walk-sneaking to take items in plain sight with a chance of not being noticed.

Alchemy
Haven't given it much thought, I never really do alchemy, just balance it out a little more I guess. Oh yeah, smoke bombs.



STEALING IN THE GAME
Here is how I would like stealing from people's houses and the like to be dealt with. First off, rich people are rich. Their houses not only do not look barren, but they will have expensive items, usually kept in heavily locked containers. This will make theivery more interesting by giving something to actually look for. But it won't be as easy to steal as Skyrim. As mentioned before, stealing an item, picking a lock, or opening a chest makes a certain amount of noise, and when NPCs hear this, they will come and investigate. Additionally, they will be more like the NPCs in Oblivion, and follow you about (I can go into the Black-Briar's house in Riften and they just let me go anywhere). They generally won't let you wander freely out of their sight. To get to an expensive item, you will usually have to get through, besides the main door, a heavily locked door to the bedroom or wherever it is, and a locked container. Even when they are asleep, most rich folk will have servants/slaves that live with them in the house and work for board, who will patrol the corridors of their fancy mansions at night or when the owners are out. This would make theft a much more risky and challenging, but also much more rewarding system than the typical Skyrim "Walk into the house with a pick or easily lifted key, go to any room without the one person in the house standing in it, and take whatever you like, which is not much". Oh yeah, and sometimes, people will carry their key attatched to them with a string or something, which means there is a risk of failing to steal the key and getting detected. Only higher level theives will be able to detect the string beforehand and attempt to cut it with a knife or dagger, which is riskier than a traditional pickpocket.

I HOPE I DON'T GET CAUGHT!
How do you avoid capture and detection in the city? Well, it's more interesting in this theoretical awesome stealth system. If too many people catch you skulking around, or if you have enough infamy, guards will be particularly watchful of you. They know you're not trustworthy. So the easiest way to stalk people to kill or steal or whatever is to keep out of view. A great place to kill someone from is the rooftops, where guards rarely look, with a carefully aimed arrow. Another possibility would be to use your speechcraft to convince them to follow you, take them into an alley and execute them out of sight. Let's assume the cities are at least a little bigger and have more streets, twists and turns and alleys than Skyrim or Oblivion or Morrownd (Though Balmora is probably the best city in the recent games in this regard). Additionally, dressing in inconspicuous clothing (nothing expensive or heavily armoured) can make you less susceptible to detection. If you are caught by the guard, a great way to escape would be by hiding. You can do this in Skyrim, but it will be more interesting in this version because you can climb on rooftops to get away. Although they can shoot at you with arrows, guards will be slower than a higher level climber and this will be an excellent avenue of escape, then jump back down somewhere hidden. Then, after a while, you can sneak into the barracks and find a list of bounty's (like the business ledgers in Skyrim) and forge them to remove your name from the list, which will remove your bounty.



Anyway, those are my ideas ATM, please offer any suggestions and ideas and tell me what you think.

Nice, but can this all be realised? I like to play stealth characters too, and this sounds amazing.

Maybe in TES VI Or VII?

To me, a speech minigame is silly and unnecessary. Fallout 3, NV and Skyrim have all had these big obnoxious [SPEECH] or [Persuade] tags next to dialogue options. They might as well put a CLICK ME sign there instead. The problem of the speech is that the NPCs are so banol and unintuitive. In Fallout 1 and 2, the speech checks were completely hidden. You'd say a certain dialogue option, and if it was a [speech] option so to speak, the speech check would be run in the background and the NPC would respond according to the result. The player would have no idea if this was or wasn't the correct dialogue option to pick. Having tags next to dialogue options is blatant handholding. Especially in TES, where a speech system could be implemented quite fantastically in combination with illusion magic and so forth.

If it doesn't tell you that you're doing anything to do with speech, I do not like that concept, because 1) It's essentially a dice-roll and 2) It removes the "You decide what you say and how you say it" part of roleplaying in the game. The speech minigame in Oblivion may have svcked, but I think without it, it's just a diceroll, and while that may be good for a tabletop RPG, it feels very uninvolved in the game. I support the concept of the character skills being an important factor, I've been arguing for it in many threads, in fact, but to have it completely skill-based is just dull and makes me forget I'm even using the skill. It's almost like this already in Skyrim. If it were to not include a minigame, they'd have to make the conversation itself a significant miniagame where the options all have a certain level of persuasion, and the success will be based largely on your persuasion level, but there is a little variation in that some paths (Which you would choose based on whichever seemed logically to be most effective for that NPC (eg. Appealing to their vanity for an arrogant character)) will make your success more likely than others. This would, however, require complex conversation trees for every instance of speech usage, which would take forever to implement in even a basic form and require tons of voice acting (or text, but that's really a bygone era in terms of gaming).

I think enemies should respond more intelligently when seeing their allies die. you could break it into three stages:



For example, if bandit 1 sees bandit 2 get hit in the head with an arrow, he will run to cover and call for help
Then once help has arrived, or bandit 1 thinks the coast is clear, he/she will examine the dead body and use clues to tell where the player is like the direction of the arrow, noise, etc.
Then they will commence a search or fortification.

In search mode they will actively search the entire known area for the player, not stopping until the npc finds him.

after a while if they cannot find the player, they will go into fortification mode.

In fortification mode, they retreat further into the dungeon, fort, town etc and stick together to make sure they cannot be assassinated. They may also set up traps and alarms to protect themselves and find the player.