That makes no economic sense, to remake a 13 year old game that was poorly received with even the fans of the series. Gothic 3 was a mistake, it is unsalvageable.
WTF, when's the last time you played it? I did like 3 years ago and I had the time of my life. With the community stuff it's one of the best RPGs I've ever played.
As for a remake, first - G3 doesn't need any, it still looks serviceable even for graphix whores. And even if it didn't - has there ever been a remake of any western RPG ever? I don't mean the "add some bugs, upscale the resolution and Bob's your uncle" kind like Beamdog shits out, I mean a proper remake like Shadow of Colossus, FF7 or Resident Evil. I don't remember any. Even non-RPG remakes are very rare. Seems it's mostly console Jap games that get those. So no, it's most likely not gonna happen.