Hawks fan, coming in peace.
I honestly don't think the Hawks even care about the regular season at this point in their run of contention. They've gone through January swoons quite regularly. The core is all late 20s to late 30s with the exception of Panarin. They absolutely pace themselves throughout the RS, and they should. President Trophies, Division Titles, and home ice just don't matter much. They just want to be ready and healthy for the playoffs.
There is no doubt that the Hawks cannot dominate teams anymore at this point, especially over the course of an 82 game season + playoffs. It isn't even a factor of the higher salaries leading to less depth on the team. The veterans are simply declining. Guys like Hossa, Keith, Seabrook, etc just can't expend max energy all season anymore, especially in a condensed schedule like this year.
As for this being the biggest game of the year for them... maybe. It is a road game against the best team in the West. The crowd should be raucous. it will be the closest thing to a playoff atmosphere that can be replicated in the regular season. And After playing one of the most compressed schedules in the league in the 1st half, the Hawks have had their first extended break of the season coming into this game, so they should be rested and it would be cool to see them play with high energy for all 3 periods. They really haven't done that yet this season. This team has shown the ability to flip the switch so to speak in the past when they want to and maybe this is Kane's way of saying that the team should treat this matchup as one of those times to try it, just to gauge where they are and what they can expect to see in the playoffs.