Sorry, but I have to disagree and that is one thing I think is not necessary and it could compromise Construct 3's elegant and professional design. And in terms of educational and professional purposes, it also isn't a good design practice, in general.
- Rainbow Event-Sheets. This will be an eyesore.
- Construct 3 would look unprofessional like Scratch.
- Increase in project size and project loading duration.
- Increase in event sheet loading.
- The Construct 3 Editor Themes would look weird, especially the "Dark Theme".
- People relying on possible messy "event colors" rather than "clean comments" and "organization".
I think the Group Colors are already enough. Even though Group colors are rarely used, but instead of helping, they actually make things confusing in the long run, professionally. They are very useful minimally used though, that's why Groups are still alright.
That would be the same case with colored events, only that it would be worse. Mixing colors in the event sheet will make things end up looking like a rainbow, which is not a good design practice, unprofessional, eyesore and untidy looking.
The goal is to design your project or events that makes it easier to read. Like commenting, grouping events and event factoring. Also, use functions, arrays, dictionaries to avoid redundant events. And if there are available addons for a task, use them for optimization and to avoid messy events.
This is a screenshot of my project
As you can observe, the Construct 3 Editor looks more professional and easy to look at and attempt to read. Because, it doesn't flash you with different colors, which is bad for the eyes if given enough time. Construct 3 Editor's current design is more professional, organized, clean and healthier to your eyes.
In terms of educational purposes, it's better to teach them how to design, organize and write clean events, logic and comments rather than being dependent on colors which is actually confusing and an eye-strain, which is bad for the health.
This will get them ready for their professional career when they learn how to make simple, neat and clean designs on their work.
I hope that shed some light on the subject. Have a nice day.