I came up with the database design for the comment table. Is this table considered to be good enough to handle a comment or can it be improved?. Please take note that the originatorId and recipientId is related to the memberId in the member table.

The ParentCommentID should be NULL for parent comments. Then you can remove the CommentType column: if the ParentCommentID is NULL then it is a parent, if not then it is a child.

Yes, remove the CommentType column.