Allow server owners to set a time limit between how long a player can submit a form. For example, if a player submits a form, they won't be able to submit another for a specific amount of time (decided by server owner), and a message will pop up saying something like "You have recently submitted a 'form name'. You may submit a 'form name' once every 'X' [Days/Weeks/Months]". Also allow server owners the option to delete forms from the StaffCP.
Allow people to meet other forum users, send private messages, and send friend requests. I think this would be a great implementation for the community. 😃