Aren't the team captains chosen as the highest hidden-elo player on the team? I just finished a dominion game and the other team's TC was level 26. There was also a level 28 and 3 30's. So how does the lowest level get TC status? He had horrible ban choices and even skipped over picking an open Rammus, giving it to us as second pick (our 1st pick chose Ashe and so was guilty of the same retardedness).

Inb4 it's because I hate American, I deserve it, I'm a terrorist, etc.

Judging by the past couple games I got into before Tera beta started up, it looks like it prioritizes AFK players.

Highest Elo gets to be team captain. This however gets overridden by premades regardless of Elo.
So if for example you have a team of 1600, 1500, 1400, 1300, 1200 and 1400, 1300, 1200 are premade. Then one of the premades will be captain and if you were the 1600, then you will be in 4th spot.