Okay, so the Fourth Doctor drastically alters Dalek history in Genesis of the Daleks (He states at the end that he's set their development back by a thousand years). Does this mean that in the new timeline, previous Dalek stories may no longer happen? I know the Doctor will still remember everything from The Daleks to Death to the Daleks, but what about the rest of the universe? With their history skewered, do the Daleks now no longer invade Earth in the 22nd century? If so, I wonder what happened to Susan, who stayed behind to help rebuild. I personally reckon that, being a Time Lady, she would remain the same while the rest of reality changed around her, but this still begs the question of what would become of her afterwards.
Then there's stories like The Chase, The Evil of the Daleks, and Day of the Daleks, all of which involved Daleks from the future travelling in time to our present era, but now that the future those Daleks hailed from is probably negated or "unwritten", are the effects of their visits to the present era still felt and recognised? E.g, do the Daleks never visit the Empire State Building in 1966 (from the POV of those outside the TARDIS)? Does Victoria Waterfield's father no longer draw the Daleks to 19th century Earth? Or is it more like the Time Crack in the latest series, where an object can be erased from existence, but everything they did up to that point still occurs? In which case, it'd be a bit of a wasted effort for the Time Lords to try and prevent their existence in the first place, if they "delete" them from the timeline, but all those poor sentient lifeforms across the universe still die horribly.
Then there's stories like The Chase, The Evil of the Daleks, and Day of the Daleks, all of which involved Daleks from the future travelling in time to our present era, but now that the future those Daleks hailed from is probably negated or "unwritten", are the effects of their visits to the present era still felt and recognised? E.g, do the Daleks never visit the Empire State Building in 1966 (from the POV of those outside the TARDIS)? Does Victoria Waterfield's father no longer draw the Daleks to 19th century Earth? Or is it more like the Time Crack in the latest series, where an object can be erased from existence, but everything they did up to that point still occurs? In which case, it'd be a bit of a wasted effort for the Time Lords to try and prevent their existence in the first place, if they "delete" them from the timeline, but all those poor sentient lifeforms across the universe still die horribly.
