I hate invisible walls. I hate them even more now because of New Vegas. Invisible walls in the gaming world? WTF?!! Ok, it was fine in Oblivion, I accepted it, but then in Fallout 3? Then in New Vegas?
I just hope Bethesda is better than Obisidian in making impassible terrian. Too many times, I tried to climb a high mountian I couldn't because it was too high. Low and behold, I get excited I found a montian or hill or ridge, I should be able to climb/jump over, and I can't because of an Invisible wall.
All I know is I will loose so much respect for Bethesda if we have invisible walls in Skyrim. You telling me Todd and company don't have any imagination to do something else? If anything, have a blizzard as was suggested, or have rocks falling off crushing your, or, have a 1000 cliff races in thier nest. You cross the boundries, you get attacked by cliff racers non stop untill you die. Since most people hate cliff racers, I will bet they will not venture futher any more.
Even with God mode on the PC, the Cliff Racers can kill you OR they keep coming and coming non stop, wher eyou can have like a 1000 you have to deal with. Eventually the player will quit.
I was so disapointed that they didn't do this in Fallout 3. The further you ventured out, the more radiation poisoning you got and would eventually die. With all the great ideas Bethesda has, they should come up with something besides, an invisible wall and "You can't venture further, Please turn back".
They can also have the endless sea they had in Morrowind and if trying to go to the other provinces, they have the endless Mountians that never ever end.