So...has anyone ever noticed that each of the three timelines have a different theme?
The Adult Timeline is about moving on from the past. Ganon, (Old) Hyrule, and the Master Sword are eradicated forevermore by the Triforce, and Hyrule Kingdom is reestablished in a new land, with the MS, Triforce, Ganon having no place there, with new threats and new holy blades being forged.
The Downfall Timeline is the opposite, with the world being UNABLE to escape the past; Ganon more or less becomes a demonic god who constantly returns no matter how many times he is destroyed and/or sealed, and Hyrule goes through golden eras followed by ages of decline. In ALBW, Link is even called, ''The hero of OUR time'', as if these cycles are expected.
The Child Timeline is interesting; since most of the events of OoT were prevented from happening, things take WAY different turns than the other two timelines, symbolizing the change of destiny the Hero of Time caused by stopping the events of the future from happening. First off, Hyrule never faces destruction like on the AT, and most people in the CT games don't even suspect Hyrule to be on the brink of it like it is on the DT all the time. Compared to the other two timelines, there is no cataclysmic destruction or near destruction of Hyrule, and there's alot less harm caused by the villains on this timeline than the other two. A new Ganon is born after the original one dies in TP, which is something that never happens on the other two timelines.