The fact we have druidic things and no potions and such and no woad is still bugging me after all these years.
Concotions that may randomly harm/heal you and buff/debuff in combat or not, could be fun.
Druidic magic can be explored a lot more, may be very interesting and have a lot of potential, for example making potions that can instantly kill or make full growth of a plant or tree, asking for weird mats...