Why
Reason 1: The game takes place in skyrim, a place and race obviously influenced by vikings, so why should the game leave out an important tool/ weapon from viking legend and culture? There is a pot city after all, who's chief resource is most likely uh.... I dunno, the OCEAN!!
I have never heard of the vikings using tridents as a weapon, nor have I heard of it in any of the famous legends. Maybe you are mistaking the trident for a rake, a gardening tool.
It's good with lots of weapon variety. But
I won't cry a river if they exclude the trident as a weapon.