Let me clarify: the game is supposed to be playable - winnable - without you doing this. The fact that you are able to do so is supposed to give you an over-and-above advantage.
I would say that if you do not manage your resources, you are giving yourself a disadvantage and playing in a way that gives you less of a chance to win.
Yes, I can see you would! That's what tells me that despite the fact that I have a great time playing the game, winning as often as the next man, and only occasionally feel it necessary to micromanage my power, that despite all that, there must be some problem here which has given you the impression that this activity is so essential, so core to playing the game, that I'm at some significant disadvantage in not having to worry about it
constantly. Or not wanting to, for that matter.
And yes, I understand you're asking for a way to not worry about it constantly also. That's probably the hard time I'm having with your point of view, actually. You seem to think this is an aspect of the game which is fundamentally important to keep - the need to micromanage one's power - but at the same time want the computer to take care of it for you. Either it's a problem having to worry about doing it all the time, in which case we need to address the route cause of it being such a necessary tactic; or it's a fun micro mechanic which can help in fringe case scenarios and thus we needn't do anything. I can see no case where it's an occasional fun micro tactic which is so onerous due to its frequency that it needs to be automated.
I can see, however, that perhaps the CTRL to automatically build reactors has partly caused the perception that in order for one to have an effective economy one needs to build as many reactors as possible and then low-power those which are superfluous.
Bear in mind, I'm not suggesting for a moment that power management
per se isn't an important aspect of the game. Simply that my decisions for power management revolve around building more reactors, capturing more planets or going after Zenith generators when I need more energy; and upgrading my mining facilities or capturing resource-rich planets when I need more crystal/metal. Occasionally I might low-power a bunch of reactors if I need to get some really expensive defenses up in a hurry. But most of the time if my energy output is hindering my resource intake I'll try to acquire more resources, not fiddle with my power plants. Honestly, I rarely find micromanaging my reactors necessary!