I can't speak to Tome Kings as I know almost nothing about them.
Personally I like that GW are making Brettonia a good faction and having a clearer divide.
No one has to be perfect, but I don't like that most of the GW lore seems to be about making factions bad, badder and, worse.
Even Stormcast in AoS went from shining golden heroes to soulless killers by 2.0.
Having everyone be "morally grey" doesn't immediately make a setting better or more mature.