I don't agree with this. Every team that's won the cup recently has been crazy strong down the middle except for Hawks, but Kane is special so they could get away without a true top 6 C. But even then their bottom 6 C's were unreal as well.
Mack is as good as any of these guys but the depth at C is severely lacking compared to these teams. Same with the Islanders, Canes, Lightning, and Panthers who will be who we have to beat if we're going to win a cup. The defense is as good as it gets but the C depth is this teams achilles heel at this point.
Lightning: Point, Cirelli, Gourde, Johnson
Caps: Backstrom, Kuzy, Eller,
Pens: Crosby, Malkin, Bonino
Kings: Kopitar, Carter, Richards
Bruins: Bergeron, Krejci, Savard
Pens: Crosby, Malkin, Staal, Talbot
Red Wings: Zetterberg, Datsyuk, Filppula,
Ducks: Getzlaf, MacDonald, Pahlsson
Canes: Staal, Brind'amour, Cullen, Weight
Lightning: Richards, Lecavalier
Well you left out some teams as well. Below is a list of all the Cup winners in the last 30 years.
Nearly all the teams have stacked defenses, while there are a few outliers like Carolina who was a fluke in general that year, or some of the Pens teams where they can get away with average defenses when they have arguably the two best players in the world in their prime with Crosby and Malkin.
Lightning - Hedman, McDonagh, Sergachev, Cernak
Lightning - Hedman, McDonagh, Sergachev, Cernak, Shattenkirk
Blues - Pietrangelo, Parayko, Bouwmeester, Edmundson, Dunn
Capitals - Carlson, Orlov, Orpik, Niskanen
Penguins - Letang, Hainsey, Schultz, Dailey, Cole, Dumoulin, Maata
Penguins - Letang, Dailey, Maata, Dumoulin, Lovejoy, Cole, Scuderi
Blackhawks - Keith, Seabrook, Hjalmarsson, Oduya
Kings - Dougthy, Voynov, Mitchell, Muzzin, Regehr, Greene, Martinez
Blackhawks - Keith, Seabrook, Hjalmarsson, Oduya, Leddy
Kings - Dougthy, Mitchell, Voynov, Scuderi, Johnson, Greene, Martinez
Bruins - Chara, Seidenberg, Kaberle, Boychuk, Ferrence
Blackhawks - Keith, Seabrook, Hjalmarsson, Cambell, Byfuglien
Penguins - Gonchar, Letang, Whitney, Orpik, Scuderi, Goligoski, Boucher
Red Wings - Lidstrom, Rafalski, Kronwall, Stuart, Lilja, Chelios, Lebda
Ducks - Niedermayer, Pronger, Beauchemin, O'Donnell, Jackman
Carolina - Hedican, Kaberle, Ward, Commodore, Wallin
Lightning - Boyle, Sydor, Kubina, Cullimore, Lukowich, Sarich
Devils - Niedermayer, Rafalski, Stevens, Zyuzin, White, Daneyko
Red Wings - Lidstrom, Chelios, Fischer, Slegr, Krupp, Olausson
Avalanche - Bourque, Blake, Foote, Miller, De Vries, Skoula, Klemm, Gusarov
Devils - Niedermayer, Rafalski, Stevens, Malakov, Daneyko, Sutton, Souray, Odelein, Mitchell
Stars - Hatcher, Zubov, Matvichuk, Sydor, Lukowich, Ludwig
Red Wings - Lidstrom, Murphy, Mironov, Fetisov, Eriksson
Red Wings - Lidstrom, Murphy, Fetisov, Konstantinov, Ward, Pusher, Ericsson
Avalanche - Ozolinsh, Foote, Gusarov, Leschyshyn, Lefebvre, Klemm, Krupp
Devils - Niedermayer, Stevens, Daneyko, Albelin, Chambers
Rangers - Leetch, Zubov, Lowe, Karpovtsev, Beukeboom, Lidster
Montreal - Desjardins, Schneider, Daigneault, Odelein, Brisebois
Penguins - Murphy, Coffey, Samuelsson, Stanton, Paek
Penguins -Murphy, Coffey, Zalapski, Stanton, Samuelsson
Having a stacked center depth didn't help the Avs when they had a crap defense, and mistakes from defenseman were what lost the Avs the series against Vegas. Not their center depth.
Defense was, is, and always will be what wins you championships.