D&D 5E Rationale behind updated Spell Lists in Tasha's Cauldron

[maceochaid]

I haven't seen this anywhere, does anyone know what are some of the guiding rationales behind the additional spells from PhB and XGtE added to class spell lists in Tasha's Cauldron? They make a decent amount of sense, I was just wondering if there was either an official message about how they chose to update those lists or if someone wiser than me identified some overarching trends that shows what the designers wanted to accomplish?

Thanks!