I didnt even know that there are roles in CTF, but for me propably the guy who give coffee to the team. And you ?
But for real I think the cryptologic part is more easy for me.
With my school’s (ASCTE) CTF team we gave each other roles based on our strong suits. I now have the role of a scripter and script kitty (we define a script kitty as someone who uses premade tools lol). From your profile, you seem like you could anything!
Idea of giving roles to peoples in CTF teams look great tho! As for me, I would clearly be anything but not the one doing cracking things :p
But for real I prefer stego/crypto/network things