I'd love to have more options to customize the email style, such as:
  • background gradients (radial and linear [choosing the angle, starting point and final point as percentage])
  • border (color, with, type [per side] and roundness [per corner])
  • margin and padding (per side)
  • add 2 fields to add custom "class" and "id" to each and every module, columns and row (useful for the custom css)
  • custom css
Most of this things can be done with just custom css.
The idea is that you add all of those options (including the custom css, so it'd be as inline css) per module, row, column, etc. so we can really customize everything.