New units will often have support abilities for their allies which tend to create more tactical gameplay. Overall this is aimed at creating a much more difficult late-game for the player where XCOM2 tends to snowball if you have managed to not suffer significant loss up until that point.
The enemy variety here introduces improved Lost with different abilities, suped-up Mutons, and Vipers, renegade Skirmishers, as well as units known as Primes that function somewhat similarly to Rulers. For the sake of brevity, I will only speak on A Better ADVENT so that you can get a grasp of what the mods by creator DerBK have to offer and decide if you would like to check those out as well. The other two mods related are A Better Barracks and A Better Campaign.
Part of a collection of mods that overhaul major aspects of the game, A Better ADVENT (ABA) is a mod primarily concerned with adding an extra challenge to the game by introducing increased enemy variety as well as improved AI and improved enemy types.
