Yes, I do plan to implement some form of limiting. I am planning to make creating a clan cost [currency].
As for the Admin Approval, that was the ancient way of doing it (PM an admin), but I will create a setting for Admin Approval

To create a "temp fix" for this, you can delete the "do=create" code from the clancp.php, and remove all references to this section from your templates (Warning: Not tested). This will revert the hack to force your users to PM you to create a clan, but will still retain all the advanced functions in the clancp.