Although Rose was marketed as the major season 1/2 companion, we also had Adam (Although that was only for two episodes) Jack and Mickey join the crew. Plus the middle season 4 had Martha briefly rejoin the TARDIS.
I think we're going to have a similar dynamic with Rory possibly (If script excerpts are any indication), as well as River Song, who appears to be in a few episodes.
I think we're going to have a similar dynamic with Rory possibly (If script excerpts are any indication), as well as River Song, who appears to be in a few episodes.