Yeah the map does get busy :(.
And the units are …well more dimensional that in AoW.
In many ways it is imho a harder game, if only because there is simply more game, more info, more to keep track off.
There are numerous improvements though.
Coming from AoW3, I think the biggest change for you is that your lower tier units stick around for much longer and retain utility pretty much to the end game.
Your basic units with late game mods are…dangerous.
Each race has a basic theme going through it, so catering to that theme helps play the race.
Vanguard are the most “vanilla,” because they are firearms based.
Use lots of overwatch and grenades (assuming you are playing against the AI here)
Your “class” is secret tech and is less central to the game, because race takes up a more obvious role.
You can play the entire game ignoring your secret tech.
Not sure why you’d want to, as there are some cool toys there.
I like Psynumbra, as Malictors and Initiates are just wonderful units imho.
Also, pretty much any tech works with any race (again mostly because races are so well designed imho.)
Another change you’ll notice imho is things sometimes take more time to get rolling compared to AoW3.