I kinda hate to use foreign words when they are not necessary. I think the only thing I don't like translated are attack names (because they really sound silly anyway and sometimes use puns that can't be easily translated) or words that use foreign language even in the original (like Oda using french or italian in some attack names). I don't like to translate proper names, but titles/nicknames with meaning like "Shirohige" or "Mugiwara" should be translated.
I had mixed feelings for the official translation here in Brazil. They would usually do a good job, but I particularly hated them calling Whitebeard "Shirohige" instead of just calling him "Barba Branca". They also translated Kurohige to "Barba Negra" (Blackbeard), but kept calling the pirate crew as the "Kurohige pirates", which was weird.
IMO, a translated text should keep its meaning, not its original sounds.