The role of translator is not only to convert one word to another but choose words that the translator believes reflects the author's meaning.
Take this 1 Peter 5:2 for example. The word (episkopeó) is used twice in the NT and means "be watchful" . If you wish to add a shade of meaning you could use the English word "oversee" which carries the connotation of authority over or you could use a more neutral word like watchful or careful like the NWT does at Hebrews 12:15.
The NWT is hardly unique in doing this, but few readers would be aware that the two verses use the same word. That is one simple example of of the tiny role translating has in perpetuating a church identity. Ultimately the identity is formed by personalities and circumstances and merely bolstered by the translation used.
The WT today using computer software could create a new translation in short order. Motives for a new translation are probably twofold, raise revenue selling millions of new Bibles and projecting an image as a scholarly religion.