He's actually been very good whenever he's actually gotten playing time, are you really going to judge his quality based on one game? If you had actually watched his other appearances for them you'd know he's been doing well...not to mention he's only 21.
I read the article someone just posted, I think the best thing they mention is usually his willingness to try and get involved and how he is always making himself available to his teammates- they hit the nail on the head with that. It is one of the biggest reasons why I thought he would workout so well in our midfield. I still think he is quality and enjoy watching him play, although I absolutely hate that it is for Real Madrid.
Same story as in Inter...he looks very talented, he's feet move well and all but he always lacks something, it's like everyone waits for him to explode but he just doesn't or can't.
I always rated Halilovic as a bigger talent. Though talent doesn't mean much today so anything can happen.
He's a good player, and will probably be great sooner or later. However it was the exact same story as with Isco, where we also had people screaming bloody murder because Real got him and not us. We will cope just fine without Kovacic, and he's not likely to create some kind of Los Merengues hegemony any time soon.
We are doing fine without him. Just like we did without Isco, or Modrić.
Still, we are doing fine because of Messi first and foremost, winning team, Lucho.. not because we dodged a bullet on those guys.