Voted no, for several reasons.
(1) Client rulers/Allied generals count against the FM limit set by the game (which is - very roughly - "1 FM per settlement"). So you can't have every settlement administered by a CR and have your FMs out in the field, at least not in the long run. Instead you won't get any children born for your family anymore. (That's unless you constantly expand without ever slowing down or consolidating, of course. But that doesn't sound much fun to me. )
(2) Limited unit slots. Nuff said.
(3) You can't have all your city administrators and your field army generals protected from enemy assassins at the same time since the current cap on spies is "1 per settlement" (and I don't want to see that changed ) and since a faction you're at war with is sending their assassins exclusively to you.
So you need to have settlements without governor anyway - unless you want your family to die out, that is .
(Currently I have my FL and all my FMs (excluding the 2 or 3 field generals) in the capital, protected by two spies. The field armies have a spy assigned to them as well. And the enemy assassins therefore concentrate on destroying markets etc in other settlements, instead of killing FM after FM every round. That's still more than annoying but at least not threatening the whole campaign. )