If the translations were for fully voiced dialogue (which thankfully isn't going to be in the game), i'd agree with you. I've played some games where English isn't the original language, and the voice acting has been terrible. Gothic being one example.
But text translations? I really don't see why the translated versions can't be just as good as original English version of a game that mostly contains written dialogue.
The difference is on subtle details about the translation as example a word: weird. That word in Spanish has at least four different words to be translated: raro, extraño, sobrecogedor, tenebroso but you have differences between the 4 words, in some context you can use just one, or two, no more. If the translator choose the wrong one you can end with a different meaning than the original. That's is why the translation by any automatic translator are so funny. The translation has to be of very high quality and the person has to know about fantasy and game settings to make a good job.