I'm not a developer, but have an idea for a Sketch plugin:
People familiar with Illustrator miss the "align to key object" function, which allows you to align selected layers to a specific one — not just the outermost one that Sketch uses.
This plugin exists https://github.com/LucienLee/AlignTo , but it requires you to pick the layer you want to align to from a dropdown. This slows you down, and if your layers aren't named well, a text list isn't very useful.
Sketch does offer a way to align to a key object: by locking the intended layer, and then using the align tools. But this is also slow, since you have to lock the layer, select all the other ones you want to align to it, use an align tool, and then unlock the layer.
I think a good alternative would be to use the last-selected layer as the "key object". (Assuming Illustrator's method of clicking the intended layer a second time without shift pressed isn't possible.)
Could this be done by a plugin, using a method like this to get the last-selected layer: http://sketchplugins.com/d/475-get-layer-selection-in-order ? Anyone interested in giving it a try?