-hp/+def Ninian with Wrath moonbow combo?

Is it possible she can become a decently hard hitter? Sure.

Is it practical? Not entirely. Her main niche is dancing. WOM is gold on a dancer. Hell, even Escape Route wouldn’t be bad for her if you did use her in combat for a bit to get her in range.

I've seen Oliva's with WuDao and Wrath combo getting +20 extra damage on top of Moonbow. She can ko 140 out of 225 that way.

Ninian won't really work because of her low attack. She'll ko 40 out of 225 hero that way. If you want to, she's a great debuffer with Distant Counter+Darkbreath as she can bait and debuff spd and atk while using her active turn to dance her team.