Um sorry I disagree
Tyr got action in Double Helix
Rommie got action in Star Crossed
Beka got action in A heart for the Faslehood Framed
Harper got some action in Into the Labyrinth.
I think its a case of how the writers write their stories and yes Captain Hunt is the main charactor, but its a ensemble show meaning a team effort and Kevin knows it and has said it on more than one occassion.