Text chat is provided as a substitute for speaking, so it should be treated similarly to subtitles or dialogue in games and other media.
Currently, the textbox is too small and positioned far above onscreen characters. It's difficult for people to read, particularly in VR.
Here are the important missing elements I've noticed.
  • The placement of text is often high above the avatar's head, making it difficult to read. It should be adjustable.
  • The background used for text isn't fully solid and neither the colour or opacity is adjustable.
  • The maximum text size has a low axial resolution in VR and can be difficult to read.
  • No way to select colour to allow differentiation between different speakers.
Here's some further reading/source articles.
I've included an image of how another VR game handles on-screen dialogue text.