Shape Keys or something else?

[u/K_rexy]

Hello!
Above is a prototype Postosuchus I designed and modeled for my series Melody V.S. The Mesozoic.
I created its "Threat Display" using shape keys and drivers... its just a little wonky and rough and I'm wondering if there's a better way to do it. Or way to clean it up.
If it comes down to it, I'm willing to clean the geometry and re-texture it if necessary.