I second all of that, except #5.

@ #3 & #4: Yes, my cabal had extreme problems to fulfill 51 cabal extermination missions, because only very few of my 25 cabal members were able to see these missions among the starsystems. I for myself could see these missions at the start, but later on they were not visible for me any longer.
And now we are stuck with finding 350 Word Bearer Sorcerors. These guys can only be found in Chaos Legion Vanguard missions, and these missions are not always on offer for everyone. Besides, they seem to appear more in medium and large missions, there are fewer to be found in small missions. At this time we managed to find a meagre 74...
Because this is our first directive this week, we are doomed not to progress at all this week! So I'd say there should be a lot of fine-tuning on cabal directives ;-)

@ #5: Inquisitors are individuals (they have always been described that way in the lore...), thus a type of 'uniform' for a cabal does not seem to be the way to go. What I would like to see is a way to display rank among the cabal members by showing how resplendent one's armor is. So standard armor for acolytes, more decorations for adepts (e.g. purity seals), some special/custom armor pieces or additions for lords and grandmasters (like a backbanner, for example). But this would be purely decorative and should be of low priority ;-)

Patience. Cabals are still very much unfinished. All of the present cabal content is new, just added for the EA start.

Oh, and by the way, at the moment each cabal member can see how much they participated in completing cabal directives, but there is no complete listing to compare each other and to see who participated at all. At least the Grandmaster should be able to see who threw their weight in and who did not ;)