Now, don't take this too seriously, as it's mostly just something silly that came to my mind, but what if Wendy's skill tree had a few skills related to flowers/petals?
1st skill: Floral flora.
Wendy learns to craft flower planter (like mushroom planter), that can be used to grow more flowers (regular flowers, dark flowers, moon flowers, forget me lots) by putting in their petals(butterflies/moon moths would work like mushroom spores and be more efficient).
Why? Well, Wendy's sisturn needs petals to work, so having easier access to them would be nice, plus you can use petals for other purposes too: beefalo treats from forget me lots (pretty good, since Wendy has synergy with beefalos), some nf from dark petals, various petal crafts from regular petals and uh, I guess bath bombs? But, more importantly, this will lead us into the next skill:
2nd skill: Sorrowful bloom (Sis-two-rn, if you will).
Wendy learns to use different kinds of petals to fuel sisturn, as well as establishing a deeper connection with it.
Wendy can now put other petals in sisturn, each giving the same effect of speeding up Abigail's leveling up, however she can also right click on a sisturn, in order to bond herself and Abigail to it. This makes the sisturn give special effects to Abigail of bonded Wendy when powered, effects depending on the type of petal used: normal petals and forget me lots - slightly faster health regen; Dark petals - slightly higher damage; Moon flowers - slightly longer shield duration.
The bonding system might seem unnecessary, but I've decided it'd be the easiest way to 1: make it so you can only have 1 sisturn buff active at a time, without making all other Wendies on the server have the same buff too, and 2: make it so you need to have and keep the skill to benefit from sisturn buffs.
That's all 