There have been a few common complaints about EventLink since its inception, ranging from pairing randomization issues to run-of-the-mill system overload crashes. However, the most common complaint had been about not being able to change pairings manually in the active round. The lack of the ability to manually pair match ups once the tournament software was fired up caused tournament organizers headaches, as they had to reboot entire tournaments if they had forgotten to enter players or players arrived late and still wanted to play.
Luckily for TOs, WotC is fairly proactive about addressing tournament software feedback (see "EventLink Updates") and just sent a Manual Pairing feature live. The addition of Manual Pairing should help alleviate some of the pain TOs had experienced in the past. Manual Pairing can be used at the TO's discretion in Casual REL mode (FNM is Casual REL, for the most part) as well as during Regular, Competitive, and Professional REL events, but only to correct mistakes made by the organizer. It can also be used in Casual REL to make sure new players don't end up facing experienced players in early rounds, improving play experiences overall.