OK, so I have a bit of time to sit down to write about translations - and I'm afraid it might just turn tl;dr, so let me know if I get too boring. Short version - it's complicated. And it depends.
First of all, languages are different, even European ones, which (mostly) stem from the same proto-language. For example in most European languages all nouns have gender, masculine, feminine or neutral, which means that even objects can be referred to as "he" or "she". In English, there are very few such nouns, which may already cause difficulties. Another example - there was this book, AFAIR by Jeanette Winterson, a first person narrative in which one could not really guess whether the narrator is a man or a woman. In English or German it's possible to do it easily. But in Slavic languages, like Russian or Polish, when a person is talking about his or her actions, verb forms change depending on their sex. If it's a very short sentence or paragraph, you can find a way to avoid it, but the whole novel? So a translator had to make an arbitrary decision and choose to translate the narrator as a man or a woman (or maybe ask the author?). Anyway, this certainly changed the book very much - but the language itself is to blame.
Or another thing - Stephen King in his "On Writing" said that a respectful author should always introduce his dialogues with "he said/she said". That using verbs like "shouted, whispered, exclaimed" is bad style. Even if what he says is true, it's true only for English. There are languages in which repetition is considered very bad style, so a translator has to invent many different ways of translating "said" and often interpret, whether a character exclaimed, mentioned, interrupted, sobbed or murmured something. Which would make a translation richer in a way.
This said, there are numerous theories of translation and nobody agrees what a good translation really is. It often depends on the book. If you want a light, easy read, the translation should first and foremost be easy to read. If, on the other hand, it is something more complicated, with the author making important points, perhaps it's a translator's duty to communicate those points, even though this may have negative influence on the language.
As for translation making a book better - certainly it's possible. Imagine you have a book that has very well-created characters, amazing world and highly interesting story line - but the language is a bit awkward, the metaphors sound strange, you stumble on some sentences, because they sound unnatural. A proficient translator will be able to smooth the language, while retaining all other elements, which are good.
However, I don't really think that German translation of TSA could be better than the original, because the second language would be inherently better in expressing some points of Bakker's philosophy. For one simple reason - a translator's work is always derivative and there is always a huge potential for misunderstanding, for missing a point, for misrepresentation. Only the author knows what he really wanted to write, a translator is left to guess.
OK, that's all for now, I think.