Definitely no reason to avoid it. Most fans of the series agree that it's not quite as good as Gothic 1&2, but imo it's still a very good game as long as you have the community patch installed. Afaik, version 1.75 is the final version, and I don't believe it's being updated any further.
http://www.worldofgothic.com/gothic3/
My personal opinion. Compared to Gothic 1&2…
+ Graphics are outstanding. Even compared to more recent crpgs, Gothic 3 has some of the most beautiful outside environments you'll see in a game.
+ Soundtrack is also outstanding. In fact, many fans feel it's the best in the series. I prefer the music in Gothic 1&2 by a small margin, but I'm in the minority.
+ World is huge. Larger by far than the earlier games with tons of places to explore.
+ More player impact on the world. You can chose to liberate entire towns and ignite large scale battles that will have permanent consequences in those areas.
- Combat is not as satisfying as the previous games.
- The majority of loot is not hand-placed like the previous games. Regular chests are somewhat randomized, and the loot in special chests is determined by the order in which you open them.
- Climbing and diving were removed, and swimming plays less of a role than before. You reach elevated areas by simply spamming jumps.
- Some people feel the game is a little too long, and I tend to agree. There are too many simple fed-ex type side quests, and many of them feel similar. The game also feels overly long because exploration isn't quite as satisfying as the earlier games. Part of that is due to the lack of hand-placed loot imo, and the fact that most buildings, caves, etc. contain nothing of value.