Current RNG nature, of per-channel 10min recycle 'reroll' is terrible.
I suggest the following system:
List of available 10 missions is refreshed once per day (at midnight reset) and is guild specific. Any member can 'accept' and 'complete' one mission they like each day, officers and above 3. Person doing it is recorded and stays in the interface. GM/Officer can 'reroll' a mission they don't like, spending some resource -- energy, or guild funds, or both. Guild with versatile appetite for the missions will have easy time assembling a list that is desirable. Or you can spend few more resources to get all 10 "SMH x5" on the list.
This way officers can work throughout the day to provide all members with missions they may like to do, rathern having to be online in the right server, at the right time, when mission can be obtained, and get lucky enough that there is an officer off server-cd that can change to take and complete.
History of what was completed 'yesterday' should also be available (potentially few days; IDEALLY with tally per week, if it's not asking too much).