(My big paragraph got deleted by Mediso I'm having to write this again from memory)

Source:https://mobile.twitter.com/AeEntropy
There has been alot of stuff found for 1.5 including the new characters
Eula Cryo/Claymore/Mondstadt and Feiyan Pyro/Cata/Liyue
Eula will be 5 star and Feiyan will be 4 star

These elemental-Weapon pairings are nothing new (Chongyun and Klee having the same pairs) but there being am increase in availability in these pairs is nice considering Klee is 5 star.

There is also going to be a housing  system in 1.5, as there have been screenshot showing a blueprints shop and the layout of the housing design menu
There isnt alot of this around yet but I hope there will be more stuff shown for this feature.

"The new materials, Dragon Lord's Crown and Bloodjade Branch are expected to drop from a weekly new boss."
Due to the new material there will be 1-2 new bosses
The one that we know is the Cryo Hypostatus..the 4th of the current 3 (Geo/Electro/Anemo)
We do not know exactly what will be giving us the material for Feiyan but we know what will give us Eula's.

And finally: "It appears the future version will permit the ability to exchange Boss Talent Materials by using Dream Solvents dropped by the weekly bosses."
This should be taken lightly- but if this does happen it will be very helpful- theres not much to comment on since we dont know mich about this apart from one thing-.
Anyways that's about it, I just thought it looked cool and I loved the characters, I may talk about these more in the future.
(Notes in comments)