Well, MoO3 lets you either manage a planet directly, or let the somewhat decent governor handle it. And you can direct the governors indirectly with various sliders.
But yea, I wouldn't suggest MoO3 though. Its a bit broken of a game really. The AI aren't able to do some key things. Ship combat favors missiles above all else. So instead of being about tactics, or style choices, it was missiles or else.
Though I think it did research better then MoO2. I found it annoying in MoO2 where you only searching one field, and one thing in that field. I much prefer MoO3 style, were everything was being researched at once, and you got break throughs semi regularly. Although, the random nature of which tech is, seems to be a hit or miss feature.
The planet habitability, I think were also better. I liked how it was a sliding scale between heat and (and I forgot the other thing), so each race could like each planet differently.
Going back to the ships, I think that MoO3 did a much better job at showing the different scale of the ships. It felt like a very nice milestone to have reached, when your ship design became the same size at the Anterians. Which just dwarfed your ships for a good part of the game.
The thing that really just kills MoO3 for me, and makes it an unplayable game, is the invisible Supply Line cost. The concept, I like. Its something along these lines; as your ships move out from your populated solar systems, they need support ships, to supply food, and fuel, and the further they go, the longer the supply line get. This length, also increase the cost.
I've gone bankrupt in the early game more then once, because I was to aggressive with my scouting. And then when I get a huge military up, I go bankrupt again, because I can't afford to move them out.
And I could never find out how much my supply lines were going to cost, or how much they were costing. And raising the military budget, and taxes like fucken crazy, couldn't cover it.
The thing with MoO3 that really killed it with me, was the invisible supply line cost.