Requesting the visa from the DOS is a simple online process the IO goes through.
If the IO says he needs to review your case before making a final decision, it could mean several things - he/she needs a supervisor to review the case because they're not authorized to approve, he/she is not experienced with DV cases, your background check is pending, your KCC file is pending, etc. You just need to be patience - the case could end up being approved in a matter of days or you may still have months of waiting.