It was pretty ridiculous in Oblivion, even more so in Morrowind. No matter how much running, jumping, grunting sounds you made, the guards or enemies would never be alerted.
I was invisible in one of the Dark Brotherhood quests where you have to kill Valen Dreth. In on of the tables with a helmet I decided to grab the helmet and grab it around while invisible infront of one of the guards. He scratched his head, like if nothing was there.
And with an invisibilty/chameleon you can auto-escape your enemies, and then they'll act as if nothing happen.
Have they done something to counter-measure this?

Like they look for areas of noise, like if you jump and you land, you make noise, and therefore attract their attention. Some might flail their weapons around in hopes of hitting you. This is of course, if they see you turn invisible.

Some enemies should be immune to your invisibility, such as bears,wolves and animals with sense of smell.
Enemies with detect life stuff should also be able to see you invisible.
This way, Chameleon won't be godmode.

I think I heard that if NPCs hear something, they got in alert mode and look for you.

kewl

For chameleon, they should just put a cap on it (i.e; 85%), like they did with armor. That way there is always that small chance you can get caught.

As for invisibility -- perhaps have a random percent chance of breaking the spell earlier than expected (i.e; pop out at 15 seconds instead of 45 seconds, while you were right in the middle of sneaking across a room full of goblins.

I agree on a cap for chameleon on invis id make it a bit more expensive on mana and have mana being consumed to keep it in effect so you could stay invisable until you run out of mana but you wouldnt be able to stay invisable to restore your mana pool.Higher level illusionists would lose less mana over time makeing the spell work longer for them.So the mage at high levels with lots of mana high mana regen could hold it a long time where youre typical warrior with much less mana could only use it for a little while in a tight spot.

Invisibility is fine, chameleon should be capped.

Honestly I thought you were going to say something different , but since you didn't I guess I will.
I think chameleon and invisibility should be comebined, or that they might already be. I will take that back if someone can give a well reasoned argument of why thosed two or so different or that they shouldn't just be the same thing.
BTW I have also never medled much in chameleon.

There has been confirmation on different levels of awareness.
Hopefully this means that some of these issues will be resolved as a direct or indirect outcome.

For instance; You are completely unnoticed, until a certain action you perform gives away your position and intentions.
Like stealing an object from a locked chest in plain view of the owner, or interacting with objects in the room.

This has bothered me a little in the past.

Perhaps perks will play a large roll in this.
I couldn't really see how at least one of the stealth perks would not have an affect to resolve one of these issues.

"Ghost Walk Perk", You are unnoticed when interacting with objects. For instance.

Chameleon really was imba in Oblivion. I remember once enchanting an entire set of attire early on in the game and thus becoming invincible at level 5 or so. While this was definitely fun it felt weird since some of the enemies I faced would literally just have had to swing their weapon around and hit me once to swat me like an annoying fly (which I, all things considered, probably was). Adding hearing and maybe even smell (although this isn’t all that accurate) to the enemies’ capabilities of detecting you sounds like a good idea.

And cast Detect Life

yeah i agree! although i normally roll an assassin/rogue style stealth char first with RPG's, in oblivion, i think i had the chameleon spell (it was the most powerful one) plus grey foxs cowl, plus a ring which also gave me 25% chameleon and i could move around invisible and beat the crap out of enemies and never come out of stealth lol! it was very OP but a lot of fun as well but not much of a challenge!

should be like you can do a lot of damage out of sneak, but then you have to come out of stealth for a few sec CD for e.g like vanish in WoW etc

Invisibility is always overpowered but it isn't much use in the middle of combat.

AS far as I know it wasn't possible to enchant something with Chameleon in Oblivion. Is that right or have I misunderstood?

Too easy to, 20% an item.

OT : Not @ Stigwa
When I first came on this forum, I said how about an 85% cap like the armour, and got ripped apart in a crapstorm of posts : "it's a single player game , why do you care?", "so you want my options reduced?", and best of all "god mode is a valid play style."
Fine, just don't tell me that balance matters so little in a single player game that poor design is perfectly acceptable.

I never had any problems with it, and honestly if you had a problem with it you dident have to use it. It IS a singleplayer game.

Definitely agree about Chameleon, it became far too easy

Honestly cant one day go by without someone demanding stuff to be stunted, gimped or removed?
As it is Skyrim will offer far less than the previous games did in terms of options and customisation, please quit demanding to simplify it even more.

These things were fine as they were and there is no reason to change them, unless you want to turn Elder Scrolls into an FPS.
Chameleon was not too easy and anyone who says it was simply played the game wrong.
Elder scrolls is not about 'the best weapon, the best spell, powerlevelling'
It is about choice.
If you dont understand that having a choice does not mean you are forced to use it, too bad.
Conversely, if you dont understand why choice is good, go play another game, do not ask for it to be removed for all those that did enjoy it.

Chameleon should just be like military camouflage http://i.dailymail.co.uk/i/pix/2009/02/14/article-1145667-037BF36E000005DC-381_468x528.jpg

Wilst invisibility should mean that no one can see you at all but if you kill and make noises they will still know your there and start hunting you.
Also invisibility should have 3 stages/levels

1: Become invisible but if you attack an enemy you become visible again - life detect still works - invisibility can not be enchanted.
2: Become invisible and stay even when attacking - life detect still works - invisibility can not be enchanted.
3: Become invisible and stay even when attacking - also safe from life detect - invisibility can be used as enchantement.

Yup, this was the main thing that resulted in my no longer playing Oblivion. This was after 100s of hours so it's not like I didn't get my money's worth out of the game, but once I figured out I could enchant my way to 100% chameleon full time and the AI had no means of dealing with it the game took on zero challenge.

I do understand folks who would say 'you didn't have to do that' and I agree. The thing is that is like telling an alcoholic he doesn't have to have another beer. It's best for an alcoholic to stay away from places serving alcohol and it's best for me to stay away from games that allow me to manipulate things to become ridiculously overpowered.

Sometimes a choice that is available to the player is only a choice because the designers never fully thought it through. You call it a choice, I call it bad design. It's a role playing game , put yourself in the player's shoes : "I can make myself permanently invisible, and never get killed, but let's have a bit of balance here, why don't I deliberately gimp myself and make it so I can die horribly, otherwise it wouldn't be fair on the monsters." If it's there, then unless you are playing some non magic, or honourable roleplay, your character would use it. You can't give options and then say don't use them, that's not what it's about.

Also very good points - No ones forcing anyone to use 100% chameleon

It should be about choice

Mainly, I want to be able to cast mega destruction spells because it's fun

Well, that chameleon amulet that you could get early on in Morrowind was OP, but I agree that removing gameplay options is a bad idea. It shouldn't be possible to achieve 100% chameleon at level 5, but so long as either incredible luck with drops, or high level illusion, enchanting, and/or alchemy are required to reach 100%, I think that more is lost by disabling a fun playstyle than allowing folks to play high level characters in easy mode if they choose.

I didn't see a problem with Invisibility. Completely invisible until you interact with something? Yeah, that's cool. Chameleon on the other hand had a bit of a problem. The problem wasn't in the spell, though, the problem was in how the AI reacted to 100% chameleon. They don't need to cap it, they just need to make the enemies act more realistic when you're wailing on them or knocking things down around them and whatnot. At the very least they should swing their weapon towards you, especially if you just attacked them without staggering them. If they have Detect Life, it would make sense for them to use it if they think there's someone skulking around with invisibility or chameleon on. That's one of the reasons the spell exists in the first place, besides seeing enemy's behind walls.

Long story short, they should make the AI more alert if you knock things down around them (cups, etc), if you're not sneaking whatsoever (loud footsteps), and if you attack them. I, for one, sure am not going to just sit around if I get punched in the gut or stabbed in the shoulder and I can't see who did it. I'm going to try and either run away or fight the invisible thing! That's just plain more realistic than having the enemy just sit there and do nothing.

indeed

or removed

I agree with what you say.
Smarter AI would be great.
An enemy should not just stand there and be killed, at the very least it should (attempt to) run away.
I would love it if everything the PC uses could also be used by NPC's and of course that includes detect life.