This month we added the ability to format text fields based off a numeric field: https://powerbi.microsoft.com/en-us/blog/power-bi-desktop-may-2018-feature-summary/#conditionalFormatting
We also are planning on adding a feature that will let you format your text based on comparisons. I’ll update this idea based on our progress on that feature.Christopher Baker commented
Lets get this done. Easy fix Excel already has rules like this.