I can see Hill having a regular 'assignment-&-orders-giver back at HQ' gig, but more like cameos and/or guest spots on single eps for SHIELD luminaries - they have their own assignments, after all.
I mean we know Joss can write/direct large ensembles, but this seems to be about 'the gang of six' on this team.
Six IS a good number; evenly divisible several ways (two groups of three, three pairs) and having that many on the Plane Of Impractical-And-Redundant Engines would still permit privacy, while a larger team would quickly develop cabin fever from the crowded confines.
Add to which despite evidence to the contrary, this isn't solely Joss's show - Jed and Maurissa may not have the same talents with large core casts.
So I'd be comfortable with this, maybe with guest spots from time to time.
Personally, I feel the second episode borrowed liberally from
the Avengers itself. And lampshaded it (and the 'perils of a new tv show') nicely.
Damsel Coulson: "They don't need me.
They {and the show itself} need{s} time."
Villainess: "Time is not on their side."
D.C.: "No, but you gave them something better. A common enemy."
{to put aside their petty squabbling for}As implied, I'm going to give AoS some more rope.