The trident worked just fine on my Niefel Jarl Pretender, in the early game, anyway-and that's pretty close to a Pretender SC. With just him, I was able to take out a huge amount of Independents.
I do wish the trident were a 1-handed weapon, though. They were sometimes used 1-handed (Retiarri gladiators, in particular, who would use them with nets, for instance), as well as 2-handed, and could even be thrown, effectively.
Concerning gladiators and the Arena, here's a reference. Infact, here's enough material here for a decent mod-nation ("I, Spartacus!" anyone?):
http://en.wikipedia.org/wiki/List_of...ladiator_types