I was reading some old fluff about the High Lords and learned how some seats are not perminate. Some of the perminate ones make sence like the:
Master of the Administrum
Represenitave of the Inquisition (who changes based on who is available)
Ecclesiarch of the Ministrum
the Fabricator General
the ruling Navigator house seat
Master of the Astronomican
Master of the Astra Telepathica

But the Grand Master of the Offico Assassinorum and the Marshel of the Adeptus Abrites have perminate seats while the remaining 3 seats are rotated by:
Lord Commander of the Segmentum Solor
Lord Commander of the Imperial Guard (arn't these 2 the same)
Cardnal of the Synod of Terra (don't they have representation from the Ecclesiarch)
the Abbess of the Adeptus Sororitas
Captin-General of the Adeptus Custodes
Chancellor of the Estate Imperium
Speaker of the Chartest Captians (who are these clowns?)

Now why do the Arbites and Assassins have a perm seat while the Guard and Sisters some times get one. And at the same time why arnt the Space Marines not represented? Although I think it admilable the SM stay out politics and see the difficulty in electing one of the 1,000 chapter masters who'd rather be fighting the enemy than fighting for a 'turn to talk'.
And as far as the Chancellor of the Estate Imperium, Captin-General of the Adeptus Custodes and Speaker of the Chartest Captians, while they have important jobs, it seems to me that some of these organizations arn't important/powerful enough to warrent a seat in front of the TV to watch the High Lords on C-Span. Its like the forman of an assembly line having a chair of the board of directors.

any thoughts?