First off, the lineup changes or lack thereof are not the issue. The issues are:
1: Not drawing penalties. This is the biggest mistake they're making. Toronto realized Boston wins on power play goals, and a free softie from Samsonov every game. So they adjusted by taking out Samsonov, and taking away the bruins power plays. This is NOT a coincidence.
2: The top 6 is brutal. Aside from Marchand winning games 3+4 and Debrusk having a hot start, these guys have done nothing good. The centers in particular are awful:
Coyle in 6 games: 0 goals, 2 assists
Zacha in 6 games: 0 goals, 2 assists
Zacha career playoffs, 18 games: 0 goals. Their first line center has never scored a playoff goal! This is a red flag, and that is an understatement
Poitras: injured
The centers are just terrible this series, to put it bluntly. It's tough because if someone is having a bad series maybe you swap 1c and 2c, or throw 3c in a top 6 role, but they are all playing equally bad so there's nowhere to go. This is where Poitras would be useful.
3: No killer instinct. This is really where the issue lies. They're passive, soft, and don't have a killer instinct. They don't play with urgency.
4: either way, we'll see what happens tomorrow. My original prediction before the series was the bruins would go up 2 or 3 games to 1, then Woll would come in, Toronto would come back and win the series. That would be a pretty cool bragging right, but I hope I don't get that right....