Hello!  So the way it was explained to me is: lack of automation specialization options is because there are more factors involved, and specialization wouldn't be nearly as effective because of it.

Here's a bit more detail:

In GC3, your production (military, social, and research) was based on your income, and you set sliders to determine how much of your spending went to each category, regardless of what terrain/bonuses you had on your planet. Before Crusade, you could also set sliders on each planet to override the global sliders to further tweak it. This meant that you could build a bunch of trade routes and then everything would start producing more.

In GC4, your production is based on your citizens + your resources.  You can train your citizens to be Scientists to increase your research output, but if you don't have a lot of tech resources, it's not going to make much of a difference at all. When you colonize the planets nearby that aren't good enough to put a governor on, those resources get sent to the closest core world, which will increase the resource output of the core world.  Building an economy starbase near your core world also helps.