I don't know if any GM will see this or if it'll make a difference, but I might as well give it a shot.
Reducing the lower sieges to once a week sounds like a good idea, except for 1 thing: Sulfur Fortres. The quest "Rescuing Elyos Captives" is always a pain in the neck if Elyos own the fort, and can mean waiting an entire week for a chance for Asmos or a dredge to take it. Maybe add in a Sulfur siege on Wednesdays, or a mechanic where the fort automatically changes to balaur every Wednesday on reset.