This is pretty subjective, because I have a very different opinion of DS1. The game had a massive, beautiful map, as you point out. That's the main reason I enjoyed the game on my one playthrough . . . journeying through the various environments was a fantastic audio-visual experience (the sound effects and music were every bit as great as the visuals and art design).
But then there was the gameplay itself. Despite having a large party, the strategic combat was underwhelming. So much of the combat was based on having everyone auto-attack, with the player simply picking individual targets for each party member (though that last part wasn't really necessary if you didn't turn the party AI down). The character customization system may have been innovative for the time, but it was incredibly dull, and didn't actually allow for much customization at all. There was a large variety of spells to choose from (which did occasionally make combat interesting), but most of the time, you could get through any encounter by having your mages auto-attack with your chosen attack spell.
Not to mention that the game pretty much lacked a story.
I don't mean to imply that I hated the game (I actually did enjoy my one playthrough of the game), but to call it a masterpiece is laughable. DS2 was considerably better (with better character customization and more interesting combat), but it had it's own problems. The more prominent 'story' was terrible, and it forced the player to wade through sometimes extensive uninteresting dialogue trees. The game also included considerably more puzzles than the original (can't remember if DS1 had any), but like the story, they were terrible.
I've only played the demo of DS3 so far, but I can already tell that I much prefer the more intense single-character combat to that of DS1. Character customization looks to be lacking (due to the apparent ability to pick up every skill by the end of the game and only customize them in 1 of 2 ways), but still far better than in DS1. I don't mind the multiplayer restrictions (other than the camera, which I have to assume will be patched on the PC), but maybe that's because I've known for a while what I would be getting with this game (I read lots of previews). To me, it looks like the game has a pretty good story with some meaningful choices, nice graphics and art design (much in keeping with DS1 and DS2), and fun combat. That's enough for me.
. . . not that I would ever shatter a disc of a game I didn't like. Seems like a bit of an overreaction.