As a Roblox developer, it is currently too hard to customize how high a Chat Bubble is per-player with the new TextChatService API; specifically, when setting BubbleChatMessageProperties through the OnBubbleAdded callback.
If Roblox is able to address this issue, it would improve my development experience because I would be able to have a variety of custom characters and NPCs that can have chat bubbles over their heads without the text being unreadable.
Currently, this value is global and affects every chat bubble, which produces undesired results if you have a variety of custom characters (see image below).
A workaround is to weld a part to each custom character in the desired chat bubble location and set that part as the adornee using DisplayBubble, but obviously that is not ideal.