I badly need the ability to specify the email bodies from the front-end event modification/creation. Without that, users cannot create a meaningful event from the front end.
I understand that the event creation form is kept as simple as possible as a lot of users does not require this. I would suggest to support all the field and have some kind of configuration (in xml onthe server, or whatever) which would specify what fields are actually enabled. This would allow the admin to specify exactly the fields needed. The default config could specify the same field that are currently available.
(ps: I would be ok also if I could enable backend access to certain users that would limit their access to certain categories/locations but I guess this would be much harder to implement).