This is possible today
Just to clarify :
You can specify what views should be available in the option-button.
That I am aware of. But if you have the "Options" button displayed then it makes the default set of Year, Month, Week and Day buttons redundant. There's no point in confusing people with two ways of accessing the same views.
(Yes, I know you could regard the four View buttons as a one-click alternative to opening the Options dialogue and then selecting your desired View, but I suspect that most casual Viewers of a calendar would prefer the four View buttons and no Options button, because currently there appears no way to remove all the additional, and for them pointless, options from the Options dialogue.)
However, if I remove the "Options" button, then it is gone for all users logged in or not and clearly for those who are calendar Maintainers rather than just viewers, there are some very helpful, even essential, options there.
You can even specify what views should be available for public and what should be available for logged-in.
That too I understand and I expect to take advantage of that facility.
AND you can also specify what menus ( calendar ( for multi calendar), views,groups,users,categories and language) should be available.
All excellent stuff for complex needs, but not where it is important to keep the interface as simple as possible for naive users who just want to check when the next meeting of their group is to be held and which is the venue for that meeting.
I assume that you want a setting for the menus for public ( no menu checked=no option button shown ) and a setting for menus for logged-in - right?
I also want the ability to show/not show any of the three columns "Views", "User Groups" and "Categories" on the "Options" dialogue.
That way, as an Administrator, you have the ability to decide whether to use the four View buttons on the Navigation Bar and not show the options Button, for users who only need to view the calendar.
Then, if your calendar is more complex, for those who only need to view the calendar without logging in, you might want to remove the Four View buttons from the navigation bar and replace them with the single "Options" button, but the dialogue that appears will probably only need to display the "Views" and "Categories" columns. (The User Groups column only seems relevant to calendar maintainers and senior ones at that! As a junior maintainer you probably don't need to worry about any user groups, just know that you have permission to add events at a particular venue or for a particular type of meeting.)
Finally, we consider the needs of those who help in maintaining the calendar (and I expect to have lots of them). They might have need to see the "User Groups" as well as the "Categories" column on the Options dialogue as a way of checking what else has been arranged in the organisation before they pick the date and venue for their activity.