There's some bias here but I think Ottawa made bigger strides this off-season than Buffalo/Detroit. The addition of Ullmark is more impactful than anything the Sabres or Red Wings did.
The issue is that for any of these teams to take a step forward one of the top-six from last year is going to have to take a step back and it might be a year too early for that. Boston got better this off-season, the Panthers are still a threat despite losing some defenders and for all the flack Toronto gets (rightfully so) they are still a regular season wagon.
The X factor for me in the Atlantic is Tampa Bay. Will be interesting to see how they do with Guentzel/McDonaugh instead of Stamkos/Sergachev. That's a team with depth issues throughout the lineup and if Kucherov isn't all world again they could finally take a step back. It seems a year too early to go against them though. Kucherov/Hedman/Vasi/Cooper can keep them in contention for as long as they are elite.
I wouldn't be totally shocked if the Atlantic ended up getting both WC spots, so that might be the best chance for the trio of breakout teams to actually make the playoffs. I don't see any of NYI, WAS, PIT, PHI being much better on paper than OTT/DET/BUF. It's probably going to be a dogfight for that last WC spot amongst those teams.
You aren't wrong how can anybody look at all 3 of Buffalo Ottawa and Detroit and say Ottawa biggiest strides?
They added a top 6 forward in Perron and a legitimate #1 goalie in Ullmark.
I don't like the Chychrun trade, I do like Jensen but I'd rather have Chychrun over Jensen, but even with tha I think Ottawa did more good than bad.
Buffalo I don't think anything good, they bought out a top 6 forward, they paid a 2nd for a 4th liner, and a top prospect for a 3rds liner center, I got them at about 78 points I just don't think they are anywhere close to a playoff team.
Detroit is a mixed bag they gave away Walman with a 2nd rounder for free for some reason, then
they replace Perron with Tarasenko, that's probably an upgrade and Tarasenko is slightly younger than Perron too.
But then Detroit signs Talbot and Campbell for some reason and now they have 4 goalies for some reason.
Ottawa seems like the only one with an actual plan which I haven't always been able to say.