Wickerbottom is badly in need of a rework. No, not just a buff like Wigfrid's, an actual rework. Here are my ideas, but feel free to contribute your own!
All of her books have a smaller, more visible and more directable area of effect (Think The Forge). This would buff The End Is Nigh, On Tentacles, and Birds Of The World while nerfing Applied Horticulture.
Tentacles will no longer attack bosses, and vice versa (Long needed On Tentacles nerf).
Tentacles from On Tentacles have half health.
Two new books: Winter Survival Guide (Sets temperture of all players within raidius to 50), and it's polar opposite, Summer Survival Guide (Sets temperture of all players within raidius to 15). Both require a Shadow Manipulator to prototype. The Winter one requires 2 Papyrus, 4 Nightmare Fuel, and 1 Blue Gem. The Summer one is the same except a Red Gem is required instead of a Blue Gem. Both books can be used 3 times and drain 40 sanity.
She gets a damage nerf like wendy since she's so old.
That's it for me! Remember to comment if you have more ideas!