This is a good feature and I was thinking of using it as main attendance going forward but I would appreciate a few features added for it to make it more friendly for guilds.
Important in my opinion
Merge playernames for same char, Eg someone name changes, Plays an alt - I guess you could do the setup under the Raid tab where you make the raids?
Remove players from the list that has quit or Left the game during progress, I know you will have a clean slate in every new instance. But you have have casuals/socials/friends join a week here and there - Also the total attendance page will get cluttered
Remove Attendance from someone whose in the logs, E.g they was in for 1-2 bosses and rage quit or whatever and you as guild want to remove attendance from them.
For fun/ nice to have
- See the amount of boss kills/attempts in a night they where in on, e.g 10/13 when you hover over the attendance, you can give color brackets maybe