I would like to suggest a “contributing factor” daily award for fortress. An extra bonus award for the top 10 contributors toward fortress completion for each day. Something enticing like extra experience, diamonds or even essence would be great to see and would get more guild members to participate.
Good idea in theory, but the issue is it will encourage people to farm fortress (hoard all the good mercenaries usually valk, and use only one or two own heroes with it to make a bunch of attacks). There are already not nearly enough lines for everyone to fill their bar, even on blockbuster, so this extra incentive would exacerbate the issue.