More abstract management layers would definitely ease micromanagement woes, but it is nevertheless a solution to the wrong problem. There is nothing wrong with micromanagement per se, if you have limited amount of planets/ships/decisions to spend your attention on. The issue arises only if this amount is increasing exponentially throughout the game. But does every 4X game have to go down this path? I think no, quite the contrary. The more things
you get to tackle at one particular moment, the less valuable these things
become in the long run. Planets dwindle to simple production numbers, ship designs become irrelevant in mass production, decisions boil down to simply choosing where to direct your armadas next. You begin playing spreadsheets and that's boring. That's the fate of all 4X games that abstract away too much. Master of Orion 3 anyone?
My suggestion instead would be to cap or otherwise limit the amount of planets/ships/etc. you can control. There are lots of ways to do it efficiently and in a logical and interesting manner. Technological incapacity, racial adaptation, penalties, taxes etc. Thirty star systems for a huge map is more than enough. One habitable planet per 3 systems is great - this way the competition for colonization is fierce, and each planet is precious for your empire. And so on and so forth.