Est: I want to make her a Speedy Flier. Worth it?

Given that most foes will fall in two hits, her doubles seem to be less important.
It could work for the enemy phase, but I doubt her player phase will improve that much.

I wouldn't be too concerned about her spd. The matchups that are most likely to be problematic is stuff like Surtr, where you really want all the atk you can get.

She has 30 spd at neutral, is it? Whitewing spear + double goad is already 41 spd without merges; meanwhile +atk puts her at 65 atk before A-skill. So if she uses death blow 3 it's 71 atk, and we can add a seal and ally support. I think anything that's fast dies to two hits of 71 atk. Maybe my summoner-supported Nowi (+spd) can survive, just barely, especially if I add some buffs of my own, but you won't have to face her because she won't have summoner support if you ever run into her. The majority of enemies that can survive two strikes of 71 will get quadded. The bigger concern would be getting some steady breath ignis coming back at her.

Just go for twoshots you basically have a 19 Mt brave weapon with armor effectiveness. When you hit shit it's gonna die. You wont kill B!Ike and Helbindi but just about everyone else is going down.