I have discovered that on the PTR all of the All-Stars skins are no longer categorized as 'Legacy' so now I am pretty confident that they will be coming back soon. :
League of Legends: Legacy Legendary Skins' Review – StrategyZero
Skins LOL: Complete Collection of League of Legends Skins
Guide to Legacy and Limited Skins – League of Legends Support
Overwatch 2: How to acquire and use Legacy Credits
How to Get Legacy Skins in Dead by Daylight - Not Any More
I have discovered that on the PTR all of the All-Stars skins are no longer categorized as 'Legacy' so now I am pretty confident that they will be coming back soon. :
Diamond 5, 104 skins(lots of legacy), Majority of champs owned, diamond Border/Icon - EpicNPC
Legacy Vault | League of Legends Wiki | Fandom
moobeat on Twitter: "The Poppy bundle + all of her legacy skins are now available in shop! More on Poppy update- https://t.co/9Kq3habPL2 https://t.co/C5xniaF8yn" / Twitter
Legacy (Universe) | League of Legends Wiki | Fandom