I second, (or fourth) the thought. I would Love to see some more unique stat changing effects go into the game.
Sacred mushroom tea that focuses the mind, - +damage, -hp
Leach Leaf biscuits, + HP steal when damage is dealt to enemies.
Plantain salve, for continued HP regeneration.
Mugwart brew, Added stamina and Run speed.
Wolfsbane stew. Kill wolves................(eeeh...)
chamomile tea. Drink before bed and get added stat boosts upon waking.

Just things like that. Maybe even invisibility style changes would be fun. But that might be more out there than the DeVs had in mind.