I ride pacelines a lot. Of course I am a favorite because of my size, but no big deal. Rotating is the key to a good paceline. If a rider stays in front too long he/she cannot hold on when they rotate back.
Most of the time I will increase my average speed 3 MPH or so in a paceline over riding solo. I think part of that is the drafting and part of that is the challenge of staying with the group.