(Does World of Warcraft have servers for all expansions?) Can I play old WoTLK? [duplicate]

I would like to start playing World of Warcraft (again, after very, very.. long time...). I heard that Cataclysm expansion greatly changes game mechanics, like deleting many stats (some of them I liked very much) or possibility to get them on items.

I don't like this 'simplification'. I very liked the old system, so I would like to play World of Warcraft: Wrath of the Lich King (+ Burning Crusade ofc.), without further expansions (Cataclysm, Pandoria or newest one). But can I do this? Are there servers for all expansions, so people don't need to buy anything more, or I would need to have at least Cataclysm or some other expansion?

I would like to play WoTLK very much, without all these very deep mechanics changes and stats deletions (it's really not the same gameplay :-[ ), and I almost bought it, but I just heard that some of the patches to new expansions can affect the old ones.

But, I suppose, something so important like game mechanics shouldn't be affected, right? ...Or they do, and I cannot play normal WoW : Wrath of the Lich King?