I think the reason MT always outputs colors as RGB/A is that Internet Explorer 11 doesn’t allow 8-digit hex values for the alpha channel. However, IE11 is not used much anymore so I could implement this now.
But my question is – do you still want MT to output color values as hex values when RGBA transparency applies? Or should MT use an RGBA value in such circumstances? The opacity value in a hex color isn’t as easy to read as the last number in an rgba color e.g. 0.7 or 50%.