[This is a short analysis]
TL;DR:
Crimson Witch is still Hu Tao's Best-in-Slot.
Diona healing and shield comparison:
Of course, as expected, 4-Maiden is still better for healing, while 2-Millelith enhance the shield.
Whether it's worth it or not, that's for you to decide!
Check here for more HP% VS Healing Bonus% comparison
Hu Tao artifacts comparison:
For non-reaction game play, Tenacity of the Millelith is not very good for DPS Hu Tao. However, it's a decent choice for burst-only gameplay.
For melt gameplay, Tenacity of the Millelith is also mediocre for Hu Tao, placing less than Crimson Witch and Gladiator. However, this build is (again) viable for burst DPS Hu Tao. Although, Crimson Witch is still the Best in Slot compared to it.
If you don't understand where the Hu Tao's number came from, you can check the previous full analysis here
