They do have the benefit of their starting goalie and top 7 dmen returning. With Rielly looking like he's rebounding and Carlo here for the full season, that is a pretty good foundation. Tanev & McCabe look fine. They're just trying to settle the 3rd pairing among 3 dmen who played here last season. And sort out whatever is going on with Woll, etc - which concerns me the most.
I do not regard Jarnkrok as an add. He was playing with these guys two years before Berube showed up. He played 33 games under Berube last season & playoffs. Only 3 new veteran players were a part of the 19 who skated in the first two games and one of them played for Berube before. Two were not in top 6 roles. I don't regard that as a big deal - not something most teams aren't dealing with at this time of the season.
A wild card is Cowan. If he becomes the second coming of Wayne Gretzky on Matthews wing ... doubtful but he's likely top 6 if he's going to do anything in this league. Now is as good a time as any. That would be enormous for their cap and helping them avoid trading the last few young assets they have to get a top 6 player. The candidates for that wing will have to get a long leash because the teams prospects and picks are so limited.
But when you change the system - by removing Marner, change all the lines or how they execute 5 on 5/PP/PK, etc, all the skaters are involved. That can be like you said "takes time to gel". Berube has talked about them searching to find chemistry. So I accept they're going through that and we're seeing them struggle some because of it. But a lot of teams go through that at this time of year - particularly with the shorter training camps.
A concern has to be Matthews. It is only two games so .. But he's not hitting yet. Takeaways are down like they were last year. Tip shots are down like he's not going to the tougher areas of the ice. But again, it is only two games. Those things did improve in the playoffs last year. If that persists, it is obviously going to be a big problem. In 10-20 games, it will be obvious if it persists. If he is chronically injured, they're in a tough situation -the Cup aspirations for this group are close to over.
I think the Wings, Sens & Habs all improved. Tampa looks like it will continue to compete though they're off to a rough start. Florida looks like it will compete without its two stars. Bruins are off to a good start. I think the Leafs regressed - they're not likely to be the 4th best team in the league anymore. Odds makers have them around 10th. Ignoring what they did to their roster and this roster is a year older, others in their division seemed to improve. It probably will be bumpier and the playoffs are not so automatic. A few key injuries and they could be in a battle to make the playoffs .. or miss them.