Notice that the "Reply to a reply" has a link to the reply that that reply is a reply to. However, this required quoting the reply to create that link. There should be a way to reply to the reply without need for quoting, but would still contain the link to the earlier reply that the subsequent reply is a reply to.
Note: If you would like your feature request / feedback about the forums to actually reach the "developers" (Wikia engineers), please submit it to Special:Contact/feedback. Wikia staff do not often read these forums, so they likely won't see your feature request / feedback here in the forums.