Mine are short and simple. I love AR the way it is ... fast, organic, fun, playful, does exactly what I want it to do. Here's the few things missing to my mind ...

1. Rulers (pixels, inches and cm) or grids or both. Two styles of grid would be good ... squares and perspective.

2. A few (very small number) of different Oil Paint brush styles.

3. Area selection tool. Even a simple square and oval area selection would be nice.

4. Splatter/drip brush.