What about embedding a publicly viewable but privately editable google calendar? You can still keep the scripting for submitting events the same, all the requirements the same, but the interface for actually inputting the events into the system would be far more straight forward and universal. You don't need to program the functionality of the calendar, just add an event in, and it has its own fields for additional info, like descriptions, links, etc.
You could distinguish between different types of events (Premium, Majors, Minors, Online, etc.) with different calendar categories (which have their own colors), which then could filter their view of, as they wish to see.
Then people can 'subscribe' to the TL google calendar, which will show these events on their own google calendars, whichever category(ies) they choose. Doing this they can even go so far as to import this onto their mobile devices or whatever... honestly the integration possibilities are endless.
This would just be much more visually helpful as a functional events calendar, with limited build time, while maintaining the current functionality, and adding additional clarity and calendar importing functionality.
Example: https://www.google.com/calendar/embed?src=nnlr0g08d617uuuo8gjmjeomj8@group.calendar.google.com&ctz=Europe/Stockholm