When starting an instance with a full party (no Duty Finder fill-ins), it would be great if it showed all the names of the members that clicked the "Commence" button instead of the number of players that are ready. That way, if the timer expires, everyone can see who is not pressing the button. The reason could be innocent, like they were AFK, but unfortunately this suggestion came to mind from a griefing attempt.

I was in a group made by Party Finder, and we were 8/8 and ready to go. When the leader queued for the duty, the window got to 7/8 before timing out, yet all the party members were saying they were ready. This 7/8 queue result happened multiple times in a row, while all 8 players continued to say "Ready" in chat. Most likely, a member of the party was not clicking the "Commence" button on purpose, probably getting a kick out of wasting 7 other people's time. Without knowing who was not clicking on the button, it is impossible to find the cause of this problem.