It certainly is! The mythical 'developer' skin where we have 100% full control of everything on the dash.
There is a method you could use now though if you wanted to have the color change based on attribute value, but you can only have one palette based on value, and by default it would affect every attribute tile, regardless of what the attribute actually is. This means if you have an attribute tile that shows 20 kw for energy and another attribute tile that has 20 celsius for temperature, they'd both be blue or whatever color you chose for that specific numeric value.
In this case, let's say you had 5 attribute tiles for temperature and 10 for other types of numeric attributes. For the temperature attribute tiles, you'd like it to show red for 90+, orange for 70-89, yellow for 60-69, light blue for 45-59 and blue for 20-44. You can do this, but for each of the non-temperature attribute tiles, you'd have to specifically force a background color for them so they aren't showing red for 90+ kilowatts on an energy-based attribute tile, or yellow for 60% humidity.
So, if you have one single type of attribute tile you'd like to use color-by-value then it's possible. This method cannot be used for multiple ranges of color-by-value.