I’ve considered that, but, ultimately, due to the nature of the plugin, this cannot work. You can’t instantiate unions during runtime without incurring a large performance overhead, as well as the fact that we cannot know what operations a union has completed. I can “store” union data as an instance under the script, however, that defeats the purpose of being strictly data-driven.
There is documentation inside the Visulie Renderer module. Roblox simply has not yet added support for function description inside the function. However, I am working on this. I have changed this in the new version, though. Take a look at this feature request:
Requiring the Visulie Renderer returns a library. Libraries in Roblox (as well as in Lua itself) have members in “camelCase”. Take a look at the math, Instance, or string libraries. Instance.new(), Instance.fromExisting(), math.max(). It’s actually more consistent to use the dot instead of colon operator in this circumstance.
TweenService only uses a colon to define Tween objects because TweenService is actually an object, not a library. You invoke object methods with colons, and library members with dots. Same thing goes with “PascalCase”. “PascalCase” for object methods, “camelCase” for library members.
I loosely follow the Luau Style Guide, which also uses .new() and not :new().
In the works! 
Animation priorities were considered in the development of this plugin, however, animation priority is more or less a band-aid solution for bad code structure. You don’t need to play animations over another. Just stop playing the previous animation and start playing the new animation on the same rig. Visulie already does that for you with loadAnimation, which overrides any previously playing animation in favor of the new one.
I don’t use TweenService at all. All the easing is done using a native implementation of different easing styles.
No, don’t feel like it’s annoying! I also use this plugin myself, so anything that can boost your workflow may also boost mine.