TB's defense was a mess this year without the veterans and the size.
People may or may not know (important) that TB has one of the best analytics guys/teams in the NHL (or so it is said).
I have pretty good faith in their directions.
They obviously couldn't predict the Sergachev injury this year.
But putting a huge duo back together from the 21-22 CUP... McDonagh-Cernak...
That's a smart move.
D-chemistry is real and important.
If you can get it back... you've fixed 1/3rd of your defense.
Given Hedman (LH) & Serg (LH) on their own pairings... there was just that other pairing needing a fix.