I guess the question is how necessary is a Dragoon to a party?
I have Gladiator Vincent, Warlord Vincent and Dragoon Freya.
Warlord was the first i trained up for pve reason. I have been using him all the time for gold/rune farming. He is decent for pve but not as good as the other champion class in pvp imo.
Dragoon Freya was the second to come. She was the one that help me clear legendary stages back then (when her stun doesnt fail). She is one of my favourite in pvp who help me stay on top 10 in the arena way back since early CBT during the mystic era. Her active skill is about 50% chance for the harder legendary boss from my experience.
I just built Gladiator not long ago for pvp reason (every champion class is very strong in the arena atm) for his 2 turns stun.
Lastly, the Berserker Vincent is actually the most fearsome unit in the arena now. He also looks very good for pve to help you dps-ing the high hp/def harder boss down. He is also the only non valiant with 25% buff aura. I rate him the most powerful unit in the game atm. The class active skill is the strongest in the game, even stronger than the sharpshooter (because of 20% higher base ATK stats) and it has 1 turn shorter CD. Sadly, I dont have enough champion to make one. Lol
Ps- imo Berserker Vincent is better than Berserker Freya because of the 25% team ATK buff aura.