Well, let's see.
3 of the last 4 cup winners. So you can't count out the Penguins or Capitals from being serious contenders even if they have flaws.
Flyers have a young D core still coming to their own, and added other supporting pieces around a stable offensive attack. They're a likely playoff team.
NYR added a star forward and top pairing defenseman. They may not be a playoff lock, but they are very much improved and should continue building.
CAR kept most of the core around that made a surprise run to an ECF. It was already a young team, so improvement from within is probable, and they have a boatload of cap space and a stocked prospect cupboard that could be used to improve even further from within, or trade for outside help immediately.
NJD added Subban, Gusev, and Jack Hughes. While the lineup leaves some to be desired, they are a better team than they were last year, and will be a tough team to play every night. If they can get surprising goaltending, they could make a run similar to two years ago.
NYI and CBJ are the only ones you can argue got worse. Granted, NYI kept most of their own and it worked under Trotz system with a very good defense, and the Jackets have a good supply of 1st/2nd line players to fill their entire forward group while also having a great defense. Both teams have questions in net, with Varlamov being inconsistent/injury prone and the CBJ group being unproven. Either way, neither team is a pushover.
There isn't one weak team, on paper, in the division. Could the CBJ, NYI, or whoever crash and burn due to goaltending? Sure, but I think the Metro is top to bottom the best division in hockey.