Vengeful fighter on Cecilia?

While I can see the immediate appeal, I feel like the skill is wasted without having an offensive special that benefits from the charging bonus.

Dunno its really hard. You'd want to fight mages anyway and if you want a more enemy phase oriented unit it might help with that, but you'd basically have no B slot against melees and her spd isn't the best. I'd personally prefer Wary Fighter especially against Armorsmashers.

Just my 2 cents though.

If you don't like other free or older armors , then yes. She is great unit and anyways all new pullable armors come either with bold or vengeful fighter , so you don't loose anything.

I am actually planning on doing a CC / VF build on her.
Her weapon is actually amazing for that as it allows her to get an easy +6 def / res.
You can also give close def on the seal and atk smoke on C slot.

So basically with just her weapon effect, she'll be around 36 def which is already decent, you gain +6 def against melee attackers and you can add buffs from allies.

I do think she is the best F2P unit we got yet ( better than Eir in my opinion ).