Opacity Slider and Reverse Button in Gradient Editor Panel

Please add an Opacity slider and a Reverse button within the gradients editor panel, so we may audition gradients thoroughly and efficiently -- Currently we have to select a gradient, leave the editor completely, try these various settings on it we were imagining might work, then return to the editor to try another one.  It's a VERY clumsy way to work with them and this change would be a huge help and time saver! Thank you-