The death knight is with you the entire game. I'm not sure what you mean by one click, one attack, but if you want your guy to attack faster, either get a bow or increase his speed. :P I suppose there's really not that many "cities". More like bases for each act. Each act has one area where you can buy stuff, initiate quests, and stuff like that. As for item variation, most of them look the same, but there are a few items out there that look pretty cool, like the Shadow items.
