I'm playing Dark Souls 2 right now and really enjoying it.
I have to say, I see where some people are coming from with their complaints about Dark Souls 2, but I also think that a lot of those people are looking at Dark Souls 1 with rose colored glasses. Now I love, LOVE, Dark Souls 1, it's one of my favorite games from the last generation, but it was not without it's problems.
People keep saying that Dark Souls 2 has worse level design because all the areas don't connect like they do in Dark Souls 1, and I have to both agree and disagree in that regard. One the one hand, it was really cool what From Software did with Dark Souls 1 in how they connected the world and made the majority of the areas connect together, but at the same time it always bothered me how small it made Lordran. The areas in Dark Souls 1 are very dense, but they aren't very big, and the entirety of Dark Souls 1 fits into probably 2 square miles, with many of the areas layered onto one another. On the other hand in Dark Souls 2, Drangleic actually feels like a large kingdom that you're traversing. Sure the areas don't really connect together all that well, but that actually makes the world feel more large and sprawling, and helps make the transitions between areas feel less jarring in terms of tone and mood.
The fact that the areas aren't interconnected in the same way as Dark Souls 1 is also the reason that you can teleport between any bonfire now, and that just makes the game a lot more convenient to traverse. In Dark Souls 1 any time you wanted to visit the giant blacksmith or something you'd have to run all the way to him and all the way back to the bonfire and every visit took 15-20 minutes because the bonfires that you could teleport to weren't conveniently located. It was like that with most merchants, and Dark Souls 2 fixes that by allowing you to get to pretty much any merchant within 30 seconds of using a bonfire. It removes a lot of the tedium from the game.
As far as level design of the areas being worse I generally disagree. Yeah, some of the areas aren't great, but some of the areas in dark souls 1 were equally bad or worse. Blighttown, the depths, lost izalith, crystal cave, tomb of the giants, the great hollow, the first part of anor londo, all those places are BAD. So it's really hard for me to condemn Dark Souls 2 for bad level design when the first game had just as many bad areas. At least in Dark Souls 2 the From Software dev team seems to have given some consideration to how the player is supposed to traverse the environment, rather than making the environment and then figuring out along the way how the player is supposed to use it.
As far as bosses, yeah, I agree that a lot of the Dark Souls 2 bosses aren't very memorable, but at the same time there are about 3 times as many bosses in Dark Souls 2 as there were in Dark Souls 1, so I'd say that between the 2 games Dark Souls 2 has just as many interesting bosses are Dark Souls 1 did, it's just that there's a lot of really uninteresting ones thrown in there as well.
So yeah, I'd say that the people who are condemning Dark Souls 2 and saying that it's worse than Dark Souls 1 in every way are whitewashing all the problems that Dark Souls 1 had. It's totally fine to prefer Dark Souls 1 (I still do), but that's no reason to say that Dark Souls 2 is a horrible game, which is what I hear from some of the series' fans.