To apply that to the current environments, you'd have to make better use of the Z-axis as well... And personally, I'd be all for that.
While I'm not huge the way GW2 executed it, the ability to jump and climb around on the terrain was probably one of the best moves it made. With few exceptions, if you could see it and you could realistically jump to it, you could reach it.
That would be great to have here. There are too many things 'off-to-the-side' that I'd like to get to, but are blocked off. :-(
This isn't something I really agree with. Well, I do agree with the statement, but not with the intent.
To me the environment itself and the exploration it lends itself to is 'content' just the same as anything else. So in that sense, yes. The area's size should be appropriate to its content.
Really though, I feel they should design the area. Figure out a scale that makes it feel immersive, engaging, and real. Then figure out the ways to best distribute other forms of content throughout.
I honestly hate it when it feels like the world and environment only exist to serve as a container for quest X, event Y, etc. This is one of the major things GW2 did NOT do right, IMO; you had this huge world, but there was a scout or an outpost always within shouting distance and each section of each zone felt like it existed just to provide a place for a dynamic event to occur.
In my mind, some places just need to 'be'. They should be parts of the world that are important simply because they are part of the world. Maybe they have their own stories and personalities, but those things exist independent of us; we're just passerbys and observers. I'd love it if I could just wander a half hour into the wilderness, not as part of a quest and not to reach some location as part of the story, but simply to explore. No mobs every 3 feet and no scouts. Maybe have hidden caches, caves, etc. but don't place them out there as a focus or goal, but simply as things you can stumble upon.
But I dunno. Maybe that's just me. :-/