Unfortunately there are no plans for Yule/Samhain updates this year, our main focus at this time is releasing Corrupted Gardens for Christmas.
However we are listening to player feedback about the lack of "seasonal content" and environment changes and it is being taken under consideration for next years roadmap.
I don't think a whole update would be asked for, maybe just a small event, such as Samhain legacies spawn faster or a redisigned pumpkin hat collectable (in diff colours) something small but fun to celebrate Samhain!
Mini event would be a great idea, if i recall we did "Halloween Horror" last year (roughly on Halloween)
I'll talk to the team and see if we can get another mini event scheduled.
New hats etc would however require a client update, there may be some leeway with the patching system but I doubt a new asset could be added.