David Alaba is a good player and he can play in many positions.
Yes, he is a multi-talented player, can play in many positions. Not every player can do it, especially for a player who play in a defensive line. As far as I know, at least Alaba can play as Central Defender, wing left back, and defensive midfielder.
It is a smart transfer of Real Madrid when they find another good and younger player with free transfer fee to replace Ramos
He is already 28 years old. He is not young anymore, but it is still a golden age for a professional football player. I am sure Alaba still in his best performance and can maintain it for more than 5 years next. Sure, this is a very smart transfer made by Real Madrid.
However, one thing I am worrying about Alaba, about his leadership.
He doesn't need to be a leader. There are still many other players who can be the leader. Don't worry about leadership, it is not a very crucial thing. I know it is important, but it is not a must for each player.