Mitchell could be great, although I can't see him doing it with tongue out of cheek. But how about getting Webb in too - he'd make an interesting sidekick. I'm surprised Mr TDavies hasn't given the Doctor more male companionship over the years...
This Saturday's episode was a fairly big change of pace from the Library two-parter.
It had some interesting ideas, but on the whole it didn't really do it for me though - most of the characters felt a bit too stereotypical to me, and most of the clothing and cabin technology were surprisingly contemporary.
The Rose thing is annoying me slightly now, hopefully the finale (does that start next week?) will be good though.
Incidentally, did anyone else notice his list of companions starting with Rose? It looks like they're considering the new stuff a lot more important than the old. Maybe that's reasonable though. It can't be denied that there's a very clear gap between old and new.
There were some good performances though, and it was an interesting concept to explore. We don't often see him having to cope by himself, and at the mercy of other people. It fleshes things out a bit.