Is there a "color wheel" for spices Are there "models" proposing relationships between spices as there are between colors?
(I understand that color is based on the physics of light and that there is no (afaik) "physics of flavor". I am using it as a metaphor)

I'd like to get more creative and adventurous with mixing spices but I've blindly overspiced a few dishes and have grown cautious... I don't really understand what I am doing sometimes when I add spices: what I am trying to achieve. 


Oregano and Marjoram  – next to each other on the "spice wheel". Marjoram is more polite.
Tarragon – has overnight dates with Cardamon but swears they are not
an "item"
Bay Leaves – no one knows what these taste like but they are really important!


I'm joking but I hope you get the gist. Is there a "model" or language with spices? ("Bay Leaves add DEPTH, damn it!!!") which informs how they can be used?
You are not the first to wonder about that and yes, there are “color wheels” approaches, two books for example are 


The Science of Spice: Understand Flavour Connections and Revolutionize your Cooking by Dr. Stuart Farrimond
The Flavour Thesaurus by Niki Segnit


Not necessarily an endorsement of these specific books (there are more with a similar concept, some discussing spices, other flavors in general), but those two should get you started in the right direction - or at least give you an idea.