Tanks that want to take it slow?

[Canadane]

Not really? While I saw more tanks hesitant to pull everything when the expansion first dropped. I seldom see them pull one pack at a time now.

ShB's levelling dungeons are somewhat easier, yeah.
But even now if you go into the older ones you'll find people do mid sized pulls more often than a full pull.

The "Pull everything" mantra has always been true for level cap dungeons, not for levelling dungeons. While you can, it's not generally included with the blanket recommendation that is true for the cap dungeons.
More than one pack at a time, yeah always do that. Everything is generally for cap dungeons.