Should things work out for Liljegren, I think Klingberg is closer to the ceiling of his potential.
Karlsson didn't drop in rankings due to performance in his draft year, the scouts ranked and preferred all of the North American defense prospects, which saw the likes of Bogosian, Schenn, Myers, Teubert going ahead of him on just about every list. He was also very small, as he was listed at 5'11 and below 160 lbs in his draft bio.
Karlsson really came around to become an elite player in his third pro season. If Liljegren had that potential, then there's no way a team wouldn't take him with a high pick considering the talent available in this draft.
I can see this year playing out like the 2012 draft, where players selected after the top two selections turned out to become better players.
If you were to redo that 2012 draft, the guy taken at #11, Filip Forsberg, would be the consensus #1 pick. Hell, the Kings got Tanner Pearson with the last pick that year, who would now likely be considered a top 10 selection from that draft class.
Wouldn't be shocked to see some "off the board" picks this year.