You can block a users access to feature instance settings but only in a global fashion so if you block him he won't be able to get to settings in any feature instance.
The way to do it is:
1. Create a new Role named NoSettings or whatever you like
2. Add the user(s) who should not be able to get to settings to this role.
3. Go into Administration > Site Settings > Security > Permissions and check your new role under "Roles NOT allowed to edit feature instance settings.
Hope that helps,
Joe