A Better Barracks overhauls your units, giving you new options to deal with all the new problems introduced by A Better Advent. It adds some of that unpredictability that I loved in Long War 2, without making it feel like a total crapshoot. Called Gatecrasher, it introduces you to Advent Gunslingers, Heavies and sneaky medical drones that heal enemies as a reflex action. It changes the feel of the game from the very first mission. It adds tons of enemy variety throughout, but most notably towards the end of the game, where you could end up overpowering the enemy. The heart of this pack is A Better Adventwhich does exactly what it says on the tin.
You also may want the Mod Config Menuwhich lets you tweak some mods directly in the options menu. The most ambitious mod for the game was one of its first, thanks to Firaxis commissioning Pavonis Interactive to produce Long War 2. The game is finally stabilised, giving modders a nice static test-bed to add new weapons, aliens and features to the squad tactics sandbox.