Hi! 🙂
Yep, it is true. Gladiators are kinda lame in C3 – sorry for that info.
C3 in general does not have 3rd profession and therefor neither does this server. 🙂 So, no, you cannot become Duelist.
Question: Do you have clan? Asking cos if you are clan-less, you should join one to get access to CH buffer. It will make your game play much easier and probably more enjoyable. If you wish, you can also join ours and if you dislike it, you can leave later (there is no penalty for changing clans on this server).
Have fun and hope to see you online soon.