This right here has me really curious as to how they plan on implementing world map restrictions and borders. They have said there will not be any invisible walls ,from what I remember reading,correct me if I am wrong? Sailing the boat around the Islands and exactly where the world map ends in particular.
On topic: OP, I can only echo your very own sentiments and inquiries myself, We can only hope that W3 is truly open world as many of us are hoping and expecting it to be. With logical,naturally occurring borders and/or restrictions,within reason. I do not think anyone wants to jarringly be ripped out of the game by obtrusive limitations and illogical obstacles.
That was quite the speech Opethian(though I did not quote the entire post as you see), but nonetheless I agree. Welcome to the forum! :welcome:
I too have high expectations of Witcher 3, but I also have a lot of faith in CDPR!
In my experience of Witcher 1 and 2, there are pros and cons regarding the openess of the world.
Witcher 1 has not an 'open world', there are perfectly natural explanations to why Geralt can't go places. A curfew, a locked gate, hell even the wild growth in the swamp never came across as an invisible wall to me. And I truly loved it! Never once did I feel restricted. How come really?
In Witcher 2 we have perhaps more open world, but 'more or less open' is a better description, because the borders are clearly there. And on my second playthrough, knowing what was where and so on, I felt restricted indeed.
So, much like in Witcher 2, I guess in Witcher 3 there will be another 'bridge out' for some reason, stopping us from exploring in that direction. I can accept that, but that reason can't account to every direction of the game map now can it?
So what natural borders do we have? With natural I do not mean from nature, so perhaps 'logical' is a better word?
Well, Nilfgaardian(or pick a nation) patrol guards setting up checkpoints, impassable mountains, dense forests or the mentioned bridges. What else? A swamp?
As for the seas, well I can only come up with two things, the first is a Nilfgaardian/Skelligan fleet.
A Nilfgaardian fleet has been launched to block any free harbour not under the Emperor's will(hell devs, we have a Roche's Blue Stripes mission right there!) and its blocking any ship(and small sailing boat) from entering the high seas to the west and south. Skellige forces amass their ships to the north and yeah, that would solve it. Until Roche single handedly sink all the Nilfgaardian ships, and then we're back at square one.
What do you think? Maybe Skellige forces take over the natural/logical border if Roche has his way with the Nilfgaardians?
And the second solution? Well the Kayran has been in the talks, though sea monsters presents a definite end to Geralt's journey(it either kills him or destroys his boat). Though Geralt fears no monsters, he hunts them for a living, so what prevents him from killing it?
A valid reason to turn around? What is(apart from a big sea monster that Geralt has no interest in fighting) a good reason to turn the boat around?
It's obvious, it's the treacherous waters itself.
The waters either being too rough to traverse and the winds too wild to sail makes the boat turn around(automatically without the player's influence) and set Geralt's boat off towards the(accepted) gaming map again. I'm thinking a buffer zone on a couple of metres before hitting an invisible wall. Of course this action is made with Geralt making a comment on the boat or cursing the weather: "She will not make it/Damn flotsam of a boat" or "Damn these waves/I have to turn back else I drown."
If Geralt is already in the water, swimming, the same mechanic can be applied. With a comment of course.
Wow, that wasn't half bad was it? Maybe not half good either I suppose. :

It beats a *boink* 'you hit an invisible wall'-solution at least.
What do you say devs?

It would be nice to get some feedback from you on this forum as well. :laughing:
EDIT: I am usually not in favour of player losing control, it might be frustrating, but rather this solution than an insivible wall to 'stare at' and run my head against. :wallbash: