I never said it was impossible, just difficult and would require a smarter terrain system than Oblivion posessed.

Also, I think that chart may be off by just a bit. I've played a few of those games, and I think the scale of Oblivion's world is slightly larger than they give it credit for. I have not played Red Dead Redemption, though, so I don't know for sure how they may have accomplished it. For Just Cause 2, however (which is just sooooo big) the landscape works in the same way that Oblivion does for the most part. They just take care to cover the whole thing in trees, grass, and rocks to make it look more interesting. For most of the island, the terrain is pretty moderate anyways, although the mountainous region has steep cliffs that seem like the Jerral Mountains in Cyrodiil.

Another game I've played with an open-ish world would be Assassin's Creed Brotherhood. They do have a more advanced looking terrain than Oblivion, but on further inspection, the bulk of their ledges and cliffs are handled through separate models that cover a section of land, and they hide the seam relatively well. World of Warcraft works just like Oblivion as well. Blizzard created some tall, unclimbable mountains, but didn't really take care to hide parts where it stretched. WoW never really attempted to be visually superior anyways, but it does what it intends to do relatively well.

One game that did have an interesting terrain system was Gothic 3, where it was able to create terrain that overhangs other terrain. This also made it so that cave entrances could be integrated seamlessly without need for a special entrance model. Here are some examples of terrain from that game.
http://pcmedia.ign.com/pc/image/article/103/1033646/risen-20091009002129223-000.jpg
http://img69.imageshack.us/img69/260/gothic3nightfallsmv2.jpg
http://www.gbase.ch/uploads/ci/shots/b_59079.jpg

The fatal flaw of Gothic 3's terrain, though, was that it was very blocky. Hopefully Skyrim, making use of more advanced and newer technology, could create a terrain system with the capabilities of Gothic 3 but much more visually appealing. As a more northern environment, whether frozen or not, there needs to be a lot of treacherous terrain, a common feature of regions that freeze and unfreeze regularly and may have once held large glaciers that carved through the landscape. Having lived in New England, for instance, I have seen the very steep mountains and valleys carved out by glaciers that I'd like to see replicated in Skyrim's engine.

Anybody want Climb Mode ala Daggerfall?

I don't want to be able to just walk up a mountain, but let me have an ice pick and I will climb http://upload.wikimedia.org/wikipedia/commons/2/26/Matterhorn-EastAndNorthside-viewedFromZermatt_landscapeformat.jpg!

Making any area unpathable in a sandbox game is irksome. In Fallout: New Vegas you can't even travel on half the map; you will see a path in between two rocks, but you are blocked from it as if there were a solid object there. Hopefully Bethesda will stay away from boxing players in to narrow and specific paths like that... I thought by now we would have moved past boxed-in environments.
Sure, using pathing to keep you inside the map constraints is one thing (although Morrowind let you swim off into the distance forever... I don't know how hard it would be to have a stretch of randomly generated mountain terrain or forest, but that would give the appearance that the game has infinite boundaries), but having unbeatable obstacles is a bother. Anything is possible with the right preparation, so why not climbing mountains? Admittedly, running up the side of a steep mountain is a little ridiculous, but a separate climbing animation, or the need for specialized equipment, whenever you go over a certain steepness would do the trick. How steep you could climb could even be made part of your athletics skill?

Someone made a mod for Morrowind like this. Not sure how it works, but have a look

http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=357

Well, there's no such thing as an "unclimbable mountain." Rock climbers can even climb vertical surfaces greater than 90 degrees, where the rock wall is not just going straight up but actually coming at you. Can you do this in armor? Of course not.

What I REALLY want to see, is climbing, period. Not jumping. Climbing walls, trees, rock faces. And yes, based on your skill as well as the equipment you are carrying (negatives for weight, bonus for things like ice picks or climbing claws) some areas will be unclimbable for your character. But someone with 100 strength, agility, acrobatics, athletics, and the proper gear should be able to climb anywhere.

there are tons of games that have steeps sides that cant be scaled. dark messiah. i believe half life 2. (both source engine games so it might because of the engine). there are some other games that i have played with steep mountainsides as well im just blanking on the names. one thing i hope the do is make stuff in general taller in skyrim. the source engine did really tall things well for some reason but gamebryo just svcked at it. just compare the main gate in dark messiah to the imperial city main gate in oblivion. the first one is waaaay more intimidating.

i also would like to see climbing in skyrim.........but you cant have any armor on and you should have a limit on how much your carrying. after all it makes no sense that you simply take your armor off but still have all 50 pounds of it in your backpack.

an easy way to keep people from getting to the top of unwanted areas would be for cliffracers to attack people after they get so high and knock them to their deaths, or have a frost atronach at the top hurl down boulders. maybe even some drunken nords peeing off the side of the mountain and it causes you to lose your grip and once again you die.

Morrowind used un-climbable, or difficult to climb cliffs to good effect. Im sure Beth know how to use them well.

According to people who played New Vegas, steep mountains that you can't run up is unrealistic.

So I've got a feeling we won't see such a feature in Skyrim.

As long as the mountains act as the boundary for the game world I would be fine.

I don't like walking over the mountains on perfectly flat landscape to get a message "You've gone to far".

I'm not sure how I feel about tall mountains in the map being unclimable. They could be difficult but not impossible.

I hated that I couldn't reach White gold tower top without paint brushes. (long grueling task)

Daggerfall had a climbing skill. Id like to see it back, as well as levitation and jump.

The climbing skill really needs to come back for a game so full of mountains. I'd say any slope steeper than 45 degrees should check your climbing skill, and you can enter climbing mode by walking straight into a wall and jumping. They should prevent you from entering climbing mode in low ceiling areas though, so a hit of the jump button wouldn't pull you out of combat or anything.

http://www.youtube.com/watch?v=Eak1VeYVx3w

Seconded

I say yes! You shouldn't be able climb the highest peak in Tamriel just zigzaging up it. You should follow a specific path, and maybe even use specific climbing gear or hire a guide. After all an unexperienced climber can't just plot a random climbing path and make it up Everest.

BLASPHEMER!!! Cough.... Need levitation back... NEED...

Yes, I'd like to see this return (but implemented a little better).

Maybe you can use tools to climb at lower levels, and then you can climb even the steepest mountains with your bare hands by level 100? that would be awesome, standing up on the top, looking out upon Skyrim and thinking;

"I did that."

the problem with new vegas was that you could be going up a hill and BAM you hit an invisible wall. no change in the grade of the incline and in fact there were a couple of areas that stopped me all of a sudden where it looked easier to get up. if they are going to put unclimbable mountains in then at least make them appear unclimbable............not some hill that any kid could go up in the park.

The only thing a nord cant climb into is a bath.

and if you have mountains you better dang well have levitation and featherfall. I wana hang glide!