That's actually not a bad idea for an addition! Wall tiles can already be un-iso'd by using the opposite Iso-Left or Iso-Right rotation/skew buttons.
As it is not quite implemented yet, you can currently (not 100% perfectly) un-iso an isometric floor tile by applying the opposite iso-rotations to it, though there is a little editing required. For example, one way to un-iso a floor is to first load an isometric floor tile:
- Tile *2
- Iso-Left rotate
- 90 Degree Rotate Right
- Iso-Left rotate x 2
This produces the original square version of the isometric floor tile in the center of the render, and just needs to be cropped out! I'll see if I can narrow down a reasonable approach to automating this process with a button