Everything from Brotherhood has been improved. Theres so much to do and you wonder if you have time them.
The Assassin management has been expanded upon for the better.....in revelations once you maxed your assns out, that was it.....you really didnt need to do much after that. Here in Revelations you can lvl them to 15...they become assn den masters at lvl 10 and each has personal quest you can do. The whole mission structure you send your assns to has been expanded on. In the era's known world, you send your assns to missions for control of said country as well as for personal goals.
Free running has recieved a nice upgrade with the hook blade and ziplines.....the hook blade gives you that extra reach in climbing as well as making impossible leaps across buildings/ledges. The hook blade can also be used as lethal and non lethal weapon. Non lethal in that you can trip people up with it and lethal that it still works as a hidden blade. Ziplines improve travel, you can use them to zip faster across the city. Also while zipping across, if there is a guard nearby you can assassinate them by pressing X to pull of the kill.