Instead of having that "alt button"you have to visually search for, just make placing fingers anywhere on the canvas mean the same thing. 1 finger means shift and two fingers mean alt. "Shift" click should always constrain to 45 degree angles while using the pen tool, similar to desktop version. Affinity Designer on iPad does this really well.

The ability to customize the quick menu. Make blending modes available along with the transparency option.

Long press finger should always give you an eyedropper.

Pen tool should give a preview line, like on desktop version.

I shouldn't have to use a modifier to pull a line after creation while using the direct select tool. Just let me drag the line to change the curve.

There is only two view modes, preview and outlines. Make that a simple button to toggle back and forth instead of the extra step of the drop down menu.

Need skew option!

As in Affinity Designer simply swiping your fill or stroke color on the menu bar should set the fill/stroke to "none".