I have to ask, how many times in the last, say, 12 months have you actually seen Karlsson play (live or on TV)? I'd be willing to bet very little, judging by these comments.
And you're comparing Karlsson to Shattenkirk, as the model of responsible Dmen? Karlsson and Shattenkirk both tend to have heavy o-zone starts, but Karlsson consistently plays against the very best opposition, while Shattenkirk is highly sheltered. Yet their overall Corsi numbers are similar. If Shattenkirk was playing top line opposition every night, instead of that role being assigned to AP and JBo, I think you'd start seeing some pretty bad Corsi and plus/minus numbers for Shatty. Karlsson, on the other hand, does not have an AP/JBo combo to spell him - that plus he has to bear the brunt of creating offense for his team, and that means pinching a lot.
Calling Karlsson a "disaster", and saying he backchecks like Ovechkin? Sorry, but it's hard to take you seriously bud.