I've seen Karlsson play for atleast 5-6 games including the Flames game last night, I will also be watching the Ottawa - Canucks game tomorrow, being a Canucks fan
I can honestly say that he will be a #1 defenseman and it won't be because of "low standards" for Ottawa, if Kimmo Timonen (was) the best defenseman since Pronger on the Flyers then I have no problem saying Karlsson will be Ottawa's best overall defense and there main go to guy besides Alfredsson or Spezza.
He is amazing, it's a real treat watching him play. I admit in the beginning of the season when I saw Karlsson on the ice I did feel like he was a liability and cringe when he has the puck along the boards. But it's quite simple, he controls the flow of a game, you can really tell, when he's on the ice he just absolutely controls the flow and make smart decisions, and he's only 19!
He's 5'11, pretty close to 6'0, I'm pretty sure he could grow a bit more and a couple years down the road he will be one of the leagues top defenseman. I have no problem saying that he could, one day be as good as Keith or similar to Neidermeyer, because his potential is sky high