I think if you gave Dark Souls a little more time it'd grow on you. The combat is a queue system, so make every button press deliberate or you'll suffer the consequences. There is a "correct" time to heal, and many enemies are programmed to do a specific attack if you heal at the "wrong" time. Try backing up and putting a static (non-moving) piece of the world between you and your foe for safe healing. I personally enjoy the voice acting very much, as you'll soon learn that there isn't a single person in the world of Dark Souls that isn't insane or going insane. Hollowing, I think they call it. Unfortunately, the terrain is something you have to learn, I probably died more from falls than anything else. As far as the little bits of land you can't walk over, if you hold your dash and press your dash again at the right time, you'll do a short jump that does the trick on stuff like that and small gaps. Oh, and you beat the second boss without getting hit you said? I think you're doing it right.
If you really got into the story from the original game, the new content will impress. It has 4 new areas, 3 new bosses, 2 new NPCs, you can get 4 new sets of armor (as far as I'm aware), all the enemies are new, but some of them are reminiscent of the enemies in Darkroot Garden. The first section of the new content uses a good chunk of resources from Darkroot Garden, but this didn't bother me as there was enough that was different that made it its own area. Of course, the new content sheds a little story on the mysterious Abysswalker Artorias. I also have to say that there's an area in the new content which genuinely frightens me when I wear headphones. If you do happen to get it on PC, you'll need a controller and I also recommend the Durante fix.