First off, I'm a windows user and a Android user. I've used Ps Touch some and as a person that does a lot of selecting and then Edit menu and Fill, content-Aware fill, this app needs Content-Aware Fill in order to remove undesired parts and items in an image.
I know you can draw a selection but how about the quick selection tool and/or magic wand tool
The blur to tool and/or smudge tool to edit out undesired sharp lines and corners would be great
And since most the mobile devices are using finger shortcuts such as pinching or widening two fingers and double or triple tapping; it would seem the pinching or widening of two fingers would be a natural shortcut to make a tool such as a pencil, brush, or selection tool bigger or smaller
Other than those it's a good start towards a mobile version of Photoshop