The most notable changes
Space Marine:
-add
Sternguard Veterans(T2), Engineer squad
New Hero Scout-sergeant, Apothecary now common unit
Imperial Guard
-add
Kasrkin, Hellhound, Engineer squad, Command Leman Russ(improves allied tanks)
Imperial Guard(Inquisitor army)
-add
Stormtroopers, Techmarine, Heavy Weapon Squad
Tier 2
Grey Knights strike squad, Chimera, Dreadnought, Death Watch tactical squad, Hellhound
Tier 3
Predator, Land Raider
Chaos
-add Chosen Marines squad, Engineer squad, Raptors
Eldar:
-add Dire Avengers
Tau:
-add
Fire Warriors, Gun Drone, Kroots, Pathfinders.
Tier 2
Xv8 crisis, Chimera, Gue'vesa(=Engineers)
Tier 3
Leman Russ, Devilfish
Orks
-become more numerous
-add Engineer squad
Tyranids
-become more more numerous
-can not supress
-add Trygon, Prime Warrior, Engineer squaq
Devilfish in Tier 3? Does it do something different than a Razorback/Chimera/Trukk as a mobile reinforce point/transport with bonus guns?
I think I'm out of the loop there.