It has all kinds of goodies you'd expect out of a more modern game engine: layer-based animation, non-fixed function rendering, the ability to work with animation skeleton positions on the server all while still supporting and integrating with existing Minecraft rendering so that you can still render items in hands and your new, more advanced entities can live side by side with all existing content. The result of this is BoneTown: a brand new entity rendering pipeline for Minecraft.
In addition for my own mods, I've been wanting to be able to use Maya and other industry standard tools. I've been frustrated with how larger and more detailed mob mods like Ice and Fire and Lycanites struggle unduly due to the inefficient rendering code in regular minecraft (which is more designed for rendering chunks which update fairly irregularly compared to animated models representing entities).
I've been spending my quarantine on a pet project of mine.
