At first she seems nothing special, then you realise she can fit a few roles:
1. Anti magic user - plenty of magic resist skills and a taunt to get them to focus on her. Could be useful for some Brutal and Tower stages.
2. Anti wind - On top of being an Ice hero, her main skills give her Wind Eater, making her deal huge damage to Wind units.
3. Sub healer for Tower - Decent healer skills paired with 2 Revive KO unit skills make her a great choice.
4. Perfect partner for Mediena - has plenty of damaging skills for elemental combos and could take Green mage sub to apply Spirit down skill to really apply increase both their damage output.
Really stretching things here. She has very limited ranged options & has a horrible list of main skills, 5 of 6 being melee "blade" skills!
Points 1 & 2 apply to all Spellblades and Point 3 really isn't anything special. Some MR units will fill this role even better, especially Salire. Her reactionary and passive skills are also poor. Unless you're a fan, she is definitely not worth it.
She does fill those roles and she can fill them all simultaneously, as well. I think element synergies in particular are only just beginning to be truly relevant and will be more so down the road. This isn’t BE where we have imbues and scores of weapons of all elements and all we need to worry about is “chain family”. The strategy that can go into team composition is so much more nuanced in wotv.
Theres nothing special about her
point 1, Whisper and Ramza does better
point 2, just icing on a cake
point3, Salire, Grace, Phoebe, or even Ayaka does the same thing in regards to healing
Point 4, I would rather MLB Gilgamesh, farmable shards and less expensive than Fryevia. Being limited means you only got such limited time to buy her shards to get her to lvl99 ¯\_(ツ)_/¯
This game isnt going to be like FFBE where you just consider “which units are going to be better at what?” Rather, I see each unit for “what do you have the potential to do?” Lots of moving parts in this game. Units being able to be direct counters for others and units being exceptional in one piece of content and absolutely irrelevant against the same enemy just two weeks later. Resistances yeah?
I think the thing to consider with any units is that i feel they come out to cater to the things to come, like we had Lucia drop and everything was gunner focused immediately after when it came to GB and Arena. From what I understand on the next GB And Arena Maps we are going to be looking at units more mag-centric and melee, and the gunners will not be flavor of the month.
That will no longer be the case if you switched out some passive skills from Fred/Lucia for the + range ones, and the ranger sub-job. You overlook the fact that the mages/spellblade has little to negative resistance to missile, and no def to hold their grounds against missiles. It's a different story if you had tanks, but Lucia could do decent work to your tanks, along side with a tank of your own