I understand what you're saying but we can't completely ignore the individuals. Horvat is a veteran with a great track record defensively. He made a mistake and/or an unfortunate event happened. It happens, that's part of the game.
When it comes to Bolduc or Aho the issue is that they attempted to stand someone up at the blue line but failed. If they cannot execute that game plan then that shouldn't be the game plan if they're in the lineup. This is why I'm so confused by what you're advocating because there seems to be a lack of consistency on when you want it applied.
Bolduc makes a play at the blue line and it directly leads to a play you don't like by Aho because he's put in a terrible position. "A" leads to "B" but you're only focusing on "B." You're going to get more of "B" if you don't correct "A" but you can't correct it because it's what you're advocating for.
With lesser players like these two these mistakes will be more common than the one Horvat made.
You're painting a broad stroke with these systemic breakdowns. Each was very different and none were really what you originally described (collapsing around the goalie).
The first goal was a misplay by Bolduc at the blue line.
The second goal Pelech tried to pick off the cross ice pass and didn't.
Then there's Wahlstrom who just had unfortunate luck on a bouncing puck. Bouncing pucks aren't systemic.
There's an issue with the team losing momentum for sure. I don't disagree there, but I don't think being more aggressive is going to fix that. Defensive systems don't work for 50 minutes at a time and then start to fail in the final 10 minutes because it's a systemic issue. That's an execution issue most likely, unless they are really told to play differently but I didn't see any indication of that last night.
If you prefer man to man I take no issue with that. At least that is something I can wrap my head around even if it isn't something I'd do. Man to man leaves players on islands a lot more and I'm not sure we have the skaters for that style. Imagine Lee being responsible for Makar?
Do you believe in blocking shots or not? I'm of the Tortorella school and believe in blocking everything you can. Some coaches don't like that at all though.
Also, just wanted to mention that I was wrong about the Dobson play. I was re-watching and his cross-ice pass that was picked off in the offensive zone was on the possession before the goal was scored. It went into the Islanders end and then the Islanders had another offensive rush before it came back and in the net.