This would be good but actually there is no really need of it and scirra is a very small company so they should focus on increasing features.
For image creating you can use gimp and paint.net they are free and they have much more functions
If that's the case, why have an editor at all. Create all your sprite artwork, regardless of how simple or complex in some other application. Because circles, triangles, and text are such intensive graphics processes, I can see why Gimp or Photoshop would be required for them.