Mark put together a feature request for the gauges here if you want to cast a vote:
Since it doesn’t have a dependency on historical data like graphing would, there’s less technical barriers to an implementation. In other words, it’s more likely to get done if it gets enough community interest. 
The challenge with HubiGraphs is it’s actually a bunch of client side JavaScript that gets injected. It’s a security risk to allow arbitrary HTML or JavaScript to be rendered directly in a tile.
That being said, I’ve helped some people on projects that render SVGs from Hubitat and they’ve used those to display custom graphics in their dashboards. In theory, a similar approach could be taken for charts like you alluded to.
One other thing we’ve been bouncing around internally is the concept of sandboxed custom components. These would allow you to run custom HTML + JS in a sandboxed environment, opening up a ton of flexibility.