Wouldn't it be cool to capture the feel of a mythic shapeshifting chase/duel? I have the glimmering of an idea of a mini-game that could be engaging for players as well as interesting in-game. I'll tell you what I'm thinking and maybe you can finish the idea.
This would become interesting and strategic if they were having to shift from flight to swimming and then from swimming to burrowing. Or if they were matching fire resistance to a fire breather, etc.
It's possible you could have different diagrams for different schools, say a reptile only, or a mythic beast only diagram. But that ups the complexity and the number of pages you have to have around.
You might make this interesting by tying it to a magic item that forces a player to shift each round (or else why ever shift from hydra once you get there?).
Or maybe when you get deeper into the chart it gets harder to get back out.
My example diagram is triangular but I imagine a complete circle of choices you could navigate around. I'd need some more silhouettes and some ideas of which creatures to use.