We know that Arda Güler complains that he doesn't get enough minutes. Especially in the Turkish press, there is a lot of news about this issue. I think he will leave Real Madrid at the end of the season. It would be best for his career if he leaves on loan and goes to the Premier League. Arda Güler is currently a side character at Real Madrid as a substitute player. At Bournemouth he can find enough minutes and become the main character. He has the potential to do that. He is only 20 years old. But he doesn't like being a substitute. I think he is a boy with a leader spirit. He can improve himself at Bournemouth. And he can move up a level.
Arda has too many good players played in his position, and makes him unable to compete. It's why i think let him leave as a loan is best decision. He gets a lot of advantage, and his club is also able in signing a new back to strengthen their squad.
I don't see negativity in this case. It's all good for his future, and he clearly must get more minutes in order to develop himself better. It's better rather than see him warmed bench, and has no use to the club.