Legends of Revolution is pretty simple compared to vanilla. If there are 20 new techs, that's a lot, I believe they included less then 20. There are some new leaders, and besides the Iroquois, I don't remember if they included another new civ.
There is also one new trait: Enlightened.
New units are the most of the inclusions, but they don't replace existing units, just are added in between the evolutionary paths, especially in the sea, where all those steam ships are added between the Ironclad era and the Destroyer/Battleship era.
I really don't remember about buildings, nor wonders and projects, so the differences are probably minimal.
Aside from all that, there is the concept of Legends, that are like world wonders but as units. This can be disabled on the options on the beginning of the game if you prefer not to use them. There aren't more then 10 of them scattered through the ages, like the 300 of Sparta, Legio X, The Barbary Corsair, 101st Airborne.
In the field of XML changes (units, buildings, resources, civics, civs, wonders, projects, specialists effects, tile yields, improvements) I think nothing else is different, but I'm not sure. Now in the optional game mechanics it may include (all of these are optional upon creating the game):
- Revolutions (RevDCM, the main component of this mod);
- Influence Driven War (battles change culture in nearby tiles);
- Start as Minors (before Writing, everybody is at war);
- Ruthless AI (the AI will do anything to crush you);
And maybe some others not present in Vanilla that I forgot about. It has been my Multiplyer mod for years already because of its stability in Out Of Sync issues, and it wasn't hard to learn because it's a lot like Vanilla. You may check Moai's "The city between 2 Rivers" story to see LoR in action.
