If you should know about any of these things…don’t tell me. :p
1. Rose and Martha meeting, having a proper civil conversation and becoming friends. Or at least not enemies. Please don’t do the obvious thing and make them hate each other, RTD and co.
2. Jack asking Rose about his immortality problem. Her being rather freaked out by what she’s done.
3. The Doctor and Rose not meeting. They’ve said goodbye already.
4. Donna not dying, Mickey not dying, Jackie not dying and Martha not dying.
5. On the subject of Mickey, having him do something cool.
6. Everyone being reasonably happy at the end. (i.e. not another repeat of Doomsday)
I have my fingers crossed.