I use circuits a lot in HE, here are some of the things I feel are missing to make it a better environment for teachers/students:
1. Obviously more components, in particular more input/output modules but until that happens a blank component that can be can have any number of pins (in and out) and text (for the name of the module) added to it by the user as a stand in for input/ouput modules. Sure the circuit won't run but it still allows sharing of the circuit diagram and code.
2. In the dashboard where it lists all of your circuits stop changing order according to last opened or at least the ability to turn that off. This is a particular nuisance when you add circuits to projects as these will often be ordered e.g. a large tutorial spread over several circuits, variations of a circuit or explanations of certain techniques that each build on the former, a group of circuits for a class etc.
3. The ability to turn off autosave and instead have a manual save button. Autosave is very problematic on slow internet connections and internet connections that disconnect. You can often work on a circuit for 20-30 minutes and the autosave gets stuck and there is no way to preserve/copy/restore what you have done.
4. The ability to turn off zooming in the circuit space with the mouse scroll and instead use + and - buttons only (like Google Maps).
5. Better annotations in the circuit space that are multi-line, easier to place a cursor and edit and minimise easier.