not to mention you also have to start making a mental list about which planets you need to ignore which icons on, as eventually you will have planets with housing and/or unemployed icons that you just can't do anything about. I especially 'love' when one of my administrators for some random reason gets unemployed and his job gets taken by a lower strata right away and then I suddenly have an unemployed administrator out of the blue for no discernible reason, and with no way to deal with him except just ignore the unemplyed icon on the planet.
Also the outliner does not warn about low amenities, so if you care about those you also have to click every single planet. Not to mention the new "increase growth" planetary decision for 1k food, that also requires three clicks per planet if you want to refresh it.
Honestly I am a little surprised that people actually defend the new system with the claim "it isn't much micro", because a lot of micro is exactly what it is. And that is coming from someone who actually likes the new system. There is so much stuff to constantly balance, and that is not trivial. The AI is now effectively unable to play the game anymore even with like +200% bonus production or whatever, yet people still claim it's trivial for players with regular production values. Sure...
And the assumption that it is now only harder if you want to min/max is not what I observed either. If you leave a planet in a suboptimal state, it is constantly polluting the outliner and thus indirectly eats the player's focus as SpectralShade said. Plus, let's take a look at the endgame situation where you want to force-build stuff on a new world and don't really care if it's the most efficient build order / timing because you have ressources to boot.
Old system:
Step 1: wait for immigration or just resettle pops until there are enough for the capital building upgrades (15)
Step 2: upgrade capital building twice
Step 3: build other buildings
Step 4: upgrade everything
Sure it was a rather tedious occupation, but you could max out your planet by visiting it maybe ~10 times. The new system doesn't even really allow that at all. It starts with the population. Let's just assume for the sake of the argument I want to force-resettle 80 pops to unlock all the building slots (80!!! old system was only 15).
Where am I taking them from? Oh I know, since I am not a min-max player, I just take them from two other colonies, and those will fill up again by themselves if I wait long enough, right? Wrong!
If I steal that many pops from somewhere, the pop-source loses all of it's buildings. So, instead of stealing 2*40 pops, I steal 3 here, 4 there, 2 there etc. Okay, so much for reducing micro, but fine.
Also, what happens now? Since I now have a planet with a gigantic population and no jobs at all, the game simulates a nice civil war there. So I have to throw massive amounts of consumer goods at them to keep them happy. Or after building everything, I have to build extra police, fight the crime, unbuild the extra police... Oh boy.
All of that might be realistic, but the point is: With the new system it is not really possible anymore to design a planet on paper and then force-build it in some sort of massive construction effort. The new system is systematically designed around some kind of organic buildup and development of the planets. And even though that is actually fun if you play Stellaris as a city builder game (that's really the only way to play it now, since it doesn't have actual AI empires anymore), that is a lot of micro.