>>410035856
When we talk about TDAs, it's less about the base at this point, and more about the way tda culture has changed it to reflect a sort of IMVU aesthetic. There are custom bases that aren't TDA but match that style still. 
The qualities you're calling out are the qualities we tend to hate on. Also rimlights and those terrible metalic shaders so many of them use.

Show me an original vocaliod TDA and it's perfectly fine. I'm not sure why people disfigured the original face so much, now everyone in a tda has a cleft lip and trashy thick eyelashes.