Doctor Who: plot and/or characterization (keys and phones)

[butterfly]

I want to post about how different it feels, on-screen, when something is done for the purposes of driving along the plot as opposed to driving along characters and relationships, but I think that I want to wait until this season of DW has finished, to see how my thoughts play out.

Because it occurred to me how plot-driven the need for Martha to have her superphone and her own key were -- she needs to use the phone during 42 in order to get the Saxon plot moving and she needs to have the key in the episode directly after 42 because the Doctor won't be able to use his.

Whereas with Rose, the superphone didn't serve any arc-purpose at all and only served episode-based plot-purposes (after she'd had it for a while) -- mostly, it was used as an emotional connection between Rose and the other characters (even in the places where it was used for plot-purposes, it was emotion-driven -- I'm thinking of Age of Steel and how the code from the phone unlocked the emotions of the Cybermen). And do we ever see Rose actually use the key as a key or was it entirely used as a marker for the Doctor? We do see her enter the TARDIS in Aliens in London, so she used it there, but the show doesn't make a big deal out of it -- we don't see her use it, the way we see Jack and Martha use it. Plus, of course, it isn't plot-necessary, as the Doctor was in the TARDIS, returning to Rose -- the point of it is to see it glowing, have Rose know the Doctor is returning to her and to have Jackie find out that he's alien. All character-arc stuff, not plot-arc stuff.

I think that this might be related to the difference in the level of character-detail we're getting between Rose's family and Martha's, but I can't be sure yet. I'm going to go think about this some more.