The idea is cool, personnally I dont “align” much stuff as I’m not a modeler but I understand the need of faster interaction.
I won’t have time to code this but hope someone got interested in the idea.
I have something to say about the UI proposal though :
Maybe instead of adding a new tab that can clutter the tabs even more ( 
@xan2622) the trigger button can be added just under the annotation UI-list in the already existing View > Annotations.
This way it falls in a related category without taking much space.