The game is still in its early stage with no info on other unreleased content (conquest), so its not easy to say which class would be more useful when this game is launched but if you dont mind me sharing from my 1 month game time:
Each faith has its own usefulness, sometimes I wish my mystics are Zeus/Kratos like in some maps. Still, you shouldnt worry about it when we are gonna get a better reroll system later anyway.
Elementalist Kiera
- I have one myself. She has the best magic buff aura in the game. Other than boosting her own spell, the aura can pretty much save anyone from getting OHKO by enemy skill damage. Nothing can go wrong with this.
Sharpshooter Cybelle
- Great dps, decent attack buff aura, highest single target spell with this path. I have this one too.
Magebane Kai (Is Ninja worth it for Gold Event? Because if I go Mind Warder Zedd, Silence and Skill Delay conflict with each other, right?)
- As you climb up to higher tier in the arena or even in legendary maps, the shadow class become less and less useful. They get pwn by both spell and heavy physical damage with no way of staying up alive. Their spells deal too little damage. Their chain attack, while quite useful in PVE, is a bad idea for the arena. If things remain unchanged, you will switch him out soon enough.
Just use him as a placeholder. I have one as an assassin which I use for farming gold mine only.
Mind Warder Zedd
- Solid choice. The skill delay is useful in both arena and against boss in harder legendary maps.
Dragoon Vincent (Because Dragoons seem to have the highest Crit... but does that even matter? It's only 1000 with Hera faith at +2)
- I prefer Vincent gladiator, but the stun passive from dragoon is really handy sometimes.
Also, do I really need a Healer? I'm at the mercy of RNG, if so...
- Definitely need one later on.