It is currently very hard to distinguish a connected arrow from a non-connected one. I have to drag the objects around to figure that out. I think it would be good to have a subtle marker of the anchors of an arrow (or any line/curve connector, really), both when drawing them, and later when they are selected. It's not necessary for the anchors to remain in the same place of the source/target object, but it would be nice to be able to see that they are there. I'm attaching a small demo of the feature as implemented in Google Slides. it's not perfect, but it gives a good idea of what could be done.

Create and save custom color palettes for easy reuse

Currently most tools are not sticky, i.e. once they are used, the app automatically changes back to the Select tool. The (only?) exception seems to be the Pen tool, which is "sticky", i.e. after tracing a stroke, the tool remains active so I can make further strokes. I think it would be nice if all tools behaved the same way in terms of stickiness, and for there to be a way to toggle the stickiness when selecting a tool. For example, if all tools are made non-sticky, then e.g. Ctrl+click or double-clicking could make them sticky. This is how the format painter tool works in Google Docs, for example — a single click selects it in a non-sticky mode, and double-clicking it selects the tool in sticky mode.

The eyedropper tool in the color picker could be usefull to select colors already used in the page.

Could be usefull to navigate p.s + for showcases

The alignment guides are excellent and very useful. I wish to evenly space multiple page or text elements (horizontally/in a row). But I found if any pages/text elements are different sizes then it foregoes the fixed spacing between elements and instead fills the space to fit within the outer selected elements. In the pic, I select the outer two elements of the top row and then shift-drag horizontally until I see the vertical red centre-line appear in the middle of the middle element. For regular sized elements that works (bottom row). Is there a way to keep the spacing between all top row elements? (i.e. pushing the right element to the right)

Make it possible to share some pages publicly

Every time user selects a color we may memorize the selection into “My last colors” palette. This should give users a possibility to create a re-usable palette of colors.

Allow multiple users to collaborate on one board

Shapes can have text inside them, that is automatically centred. This will save the additional steps of creating a text box (then grouping them together) in the future. Especially useful when moving things around (as you are doodling/explaining/expanding in real time).