Is it a common practice to change the title into something different?
This occurs pretty often, it is called Cultural streamlining


  To accommodate American viewers, anime dubbed in the United States is usually modified to suggest it occurs within the United States or a fictional country thus resembling it. This is commonly achieved by substituting Japanese elements in a series by elements drawn from American popular culture, modifying food or other products to resemble their American equivalents and by replacing Japanese writing with English writing.


A very simple example as was given on the wiki is Ash from the Pokemon series carrying a sandwich in the American version while in the Japanese version he carries a onigiri

The same counts for the titles of those kind of series, aka the wandering samurai instead of Rurouni Kenshin. Because most of their audience would not even know what a Rurouni is. 

Changes such as Samurai X usually are done for audience stereotyping, a series called Wandering samurai is less likely to be watched by a female audience. While the name Samurai X is also more attractive to the female audience, which broadens their audience for more income of the series. 

In the end all Renaming of characters/titles is mainly for marketing purposes.