Sorry, one last question for those in the know:

- What is the late game like?

I ask this and mean the following: I rarely play a TBS game to completion, and it bothers me. HOMM3 was the closest I could get to a "good" sense of closure; in most of the other TBSs I have played, I find the late game problematic for the following reasons (if you want, you can see my threads from 2 years ago on my ideas of how to rescue Late Game in E:WOM, e.g. here and to a lesser degree here.) 

1. Tedious, gigantic micromanagement: By late game in most 4x TBS, your empire is quite large, and you need an hour just to browse through all the crap you have going to see what's what, then make decisions about it, etc. It's often a pain. I play games to have fun, not mimic office management. This includes GalCiv2 and my fears of E:FE as well. For this reason, I never finished a game of CivIV, not one.  

2. Competition: Rarely do I have a game when I have a decent competetor late game. Either I have already been wiped out in the Early Game, or I survive to Mid Game, which is often still interesting, but usually start pulling away at the end of it. By the start of Late Game, I am usually so far ahead that the competition has no chance, but am still miles away from my victory conditions.  

3. Lack of Options (boredom): Often, in Late Game, I've already done everything there is to do. There's no real exciting research that will change anything significantly, my cities (planets, colonies, whatever) have already been fully built up, and there is nothing left to build. GalCiv2 and CivIV were particularly guilty of this. I can only build tanks (spaceships) and move them around. This is particularly annoying for a Builder kind of person (that's me, the opposite of a Warmonger), and I usually start wars just for something to DO. I click End Turn and drink coffee, eventually go to bed, and never bother to re-load the game again.

What do the wise folk say about DW in this regard?

thank you

No experience with Distant Worlds, but you play on too big maps. It's like any game of M&M:Heroes that goes to month 3. Everything is built and it's just a matter of defeating the enemy superheroes.

So play on smaller maps so the games can actually finish.

In RTS this is solved by Victory Points.

HOMM3: In the Wake of Gods had a victory points option that you could use, and it's quite possible it will eventually be used in the HOMM3 rewrite VCMI (and maybe the HOMM2 rewrite fheroes2 too).  So it doesn't have to be restricted to RTS games.

"Random elements" is a bit vague. You mean like in research? No, the tech tree is static. While it offers some specific techs to some races there are no random elements there, like in SotS or MoO1. You can customize plenty of things though. Maps and different games do feel very different (there's lots of replayability for sure). You can set up your opponents to random if you like so that you don't know to whom you're up against. But AIs behaviour is static, they always behave the same way (I mean the races style).

About creating your own race and injecting graphics and own ship models. This one is more for the modders. About the race setup, you can't create one from scratch unfortunately (at least not in-game). You can set the trivials though (empire name, color, logo) and you can pick the government you start with but that's pretty much it.

About automation. There's plenty of it, the options are very varied. Now, for your profile (GC2, MoO2&3, SotS) now entering in the DW universe. I would say it depends. Do you consider yourself a micro-manager maniac? Or are you ok with some parts of your empire to run for themselves? I'm asking this because depending on your micro-management profile the right amount of automation you'll need. I run fully manual, with a couple of suggestions left on. However I know of many folks that prefer to automate ship design (common) or fleets, or research (less common). So judge how much of a "control-freak" you are. If a big control-freak then fully manual, if you're more of an adventurer than a strategist then almost fully automated, if you're in between then I would recommend you start with ship design, fleets, exploration and construction in automatic. Concentrate more in eXpansion (colonization), research, diplomacy and watch what's going on to learn how the AI does it. Then switch it off gradually till you feel comfortable.