It’s possible with a few steps:
1) Go to main site, ‘Users->User Role Editor’, select ‘administrator’ role;
2) Revoke from ‘administrator’ role all capabilities, which you think are not needed to it.
3) Use “Admin menu access” add-on (I suppose you activated it earlier) in order to block for ‘administrator’ role admin menu items, which you can not block via user capabilities, like menu items protected by ‘manage_options’ capability, which is used as WordPress itself (Settings menu) and a lot of other plugins.
4) Go to “Network Admin->Users->User Role Editor”, click “Update” to replicate modified ‘administrator’ role and “Admin menu” settings made for it to all other existing sites of the network.
You have to make this after any new plugin network activation. While URE copies automatically all roles from the main site to a new created site, it does not make this for the add-on settings made for the main site. So you have to make it manually or via custom PHP code.
