Idea for the time-line when it comes around:

It would be really cool to see a bar you can drag in the Runeterran map to go through the entire timeline.

Drag the map back (3000?) years to see Icathia green, no void. Shurima is well established and Valoranian civilisation miniscule. (Now that I think about it, I wonder what was happening over there during this time?). Drag back to see the Blessed Isles, before the ruination. It would be flexible, you could do so much with it! Pre-rune wars! So many possibilities.

EDIT: Amazing idea by Sir Poodles his comment -

I'd be thrilled with this, under one condition. I would like there to be some sort of visual effect masking certain places at certain points in the past. (I'm thinking maybe a thick fog, like the fog of war in-game?) This would make it so that the feature could release before they've filled out every single teensy bit in the timeline, allow them to preserve mysteries and story hooks, and allow for theorizing or guessing about the gaps in our knowledge.