Which makes this idea even more pointless. Forcing me to tell my sectors to build what I want when I want it makes zero sense.
Just let me build what I want. There is no reason to have a middleman.
The idea is that if you controll alot of planets you have to use the horrible ways to get acces to your sectors space stations I had games where I wanted to simultaniously build 40 ships while having only 9 or so cores sector planets. Can you imagine the fun of clicking through the sector menue a million times.
On idea of my suggestion is to be able to give the sector some composition you want them to build, lets say 3 corvettes for every destroyer or something like that (could possible even differenciate types like 1* corvette of type 1 vs 2* corvette of type 2) and then the sectors builds the fleet by him self as long as he can afford it and as soon as he can afford more he builds more. No need for unnecessary micro managment.
I can understand why you don't want to give more controll to the stupid sector ai, however I think they are an important and possible in the future interesting part of the game since they allow the devs to give players more macro stuff todo while not overloading you with tons of repetetetiv micro.
The major flaws with the OP's idea are that it is unnecessarily detrimental to large empires for no real reason (possibly because the OP can't Be Big) offered and the idea isn't very well fleshed out to begin with. I'm not even sure if it's possible for sectors to build anything besides Auto designs.
Why this idea targets large empires that much is quite the opposite of what you believe. I usually play heavily expansionist and aggressive since it's the best way of winning in stellaris at the moment as far as I can tell (and wide is usually more fun for me). I would love to give smaller empires chances without having to form huge alliances. That doesn't mean that small empires should defeate larger empires that are as developed, but that small empires that are better developed should have a chance against big empires that aren't.
As far as I can tell the devs think that Tall empires could use a hand aswell if you consider the upcoming patch.