Interesting take. I do love the idea of depth and using that as an advantage over teams.
But I'd say historically, the team with a top 3-4 players has been more likely to win the Cup than the team with the better depth.
Teams like the Pens, Hawks, and Kings with sustained Cup windows (and multiple cups each) all have the same thing in common - a really strong core of 3-4 elite players that are part of every Cup winner over their 5-10 year window. Those 3 teams won 8 cups over 9 years combined.
The opposite is the St. Blues formula which is more about excellent depth of 15 players, versus elite 3-4 players, but winning a cup with this model is actually quite rare. Teams with this type of depth often win a series or two, but very rarely actually hoist the cup.
Looking at past champs like Pittsburg (Crosby, Malkin, Letang), Chicago (Kane, Toews, Keith/Seabrook), and LA (Kopitar, Doughty, Brown/Carter), or even more recent winners like TB (Stamkos, Kucherov/Point, Hedman) and the Caps (Ovechkin, Backstrom/Kuznetsov, Carlson) you can see they are more about an elite core, than being deeper than the other team, which is especially important in 7 game series after 7 game series come playoffs.
So, the reality is the Sens core (Tkachuk, Stutzle, Chabot right now) is actually REALLY important in terms of seeing them become truly elite impact players, otherwise a Cup is highly unlikely. This is basically table stakes for the most part. It's why the Stutzle/Sanderson picks were so important, and why we get another shot at a core piece this year that could become part of that elite formula.