As guilds play a major role in the day-to-day life for gw2 player, the “last online” function would highly benefit guilds who have a full roster (regardless of their current max roster size) will be able to increase the efficiency of its roster, organize better group events within itself, promoting dungeon runs and benefit a greater amount of players. Having better guild management options will encourage current loyal players of gw2 to encourage more people to learn and come to enjoy the game.
Right now every ‘deadwood’ in a guild log is a potential new gamer waiting to fall in love with the game.