I've played "Galactic Civilizations Ultimate Edition" by Stardock.
I liked it a little bit. Things I hated were:
Combat was incredibly boring and incredibly difficult to win.
You either crushed, or were crushed, and usually you lost, at great expense.
Diplomacy was a joke. No matter what you did, you pretty much got treated
like crap by everyone.
There was always something missing. No matter what you tried, how hard
you worked, you got an economic crisis, or a political crisis. Not rewards for hard
work.... hard work gave you just slightly (VERY slightly) less severe disasters.
You had to invest dozens of hours of real-time for anything to happen, and then, surprise,
you lose. Just massively frustrating.....there were never any clear signs to guide you in what actions would be effective, just crisis after crisis after crisis. Exhausting and depressing.
I more-or-less enjoyed Civilization 3, Alpha Centauri and the first two Empire Earth games.
I really liked the Star Wars game that gave you the ability to do three things: look at the whole galaxy, and move ships around, fight with ships inside a solar system, and fight with units on a planetary surface. It lacked much depth in politics and economics, but
I always felt like I knew what was going on.....not like the game was playing a "Three Card Monte" on me with charts and menus and graphs that you'd have to be a literal rocket scientist to decipher.
I don't mind some complexity IF there is a very very very very detailed and interactive tutorial, and a really world-class users manual.
So, would I hate Master of Orion?

I think you would like MOO 2 very much. It does not suffer from any of those problems. I loved MOO2 and picked up Gal Civ because everyone compared them. Turns out they were nothing alike. I couldn't stand Gal Civ for a long time. Its grown on me now, but that is another story.

I think there is a good chance you won't hate MoO/MoO2. The problems you have with GalCiv, for instance either shouldn't exist or can be minimized. I'll talk about MoO2, since it is the newer of the two and has more options than the original.
In terms of diplomacy, races, more or less, behave rationally. If you get too powerful or encroach on their solar systems, they'll get upset, but otherwise, it isn't too hard to keep them happy. If one wants to, diplomacy can be further influenced by creating a custom race and choosing racial abilities (for better trading, be more likable, repulsive, etc).
The combat is also a little better. Like GalCiv, you can design your own ships; not the look of them so much, but you can determine what systems are included in the ship. The combats are better than GalCiv, in my opinion, since they allow the player to actively control each ship (choosing target, moving them around the grid, etc). In GalCiv, it ship combat was tantamount to watching a movie, iirc.
There is a tutorial difficulty setting. It has literally been 13 or 14 years since I played on that setting, but I don't recall it being that difficult to pick up the basics. I don't think the tutorial was good for figuring out build orders and strategy, but it certainly allowed me to learn enough to figure that stuff out for myself.
The way MoO2 treats colonies is very similar to the way that the Civilization games of the same period treated cities. There are colonists, in 1 million person units, that are utilized in one of 3 categories (food, production, research). Buildings that are constructed show up in the "city" screen of each colony. There is a build queue for each colony. Basically, I remember thinking of it as a sort of Civilization in space.
I think i answered most of your major points, I hope that helps you decide.

I always found Moo very boring (back when it was released) so I can't say I am veru objective on this. I found GalCiv 1 and 2, much better experiences and far less boring. I never liked the customization of ships and GalCiv 2 took it to the extreme.
I never got really into Moo2 either.
I disagree about the diplomacy in GalCiv and especially 2, since I found it one of the few very strong parts of the game.
If you have the money, get Moo here, you can't go very wrong, but also if you want have a look at Armada 2526 that was recently released and I like it a lot.
Forget what I said.
I just bought the games.