Necrons, Chaos Marines, a lot of Space Marine chapters lost stuff.
Tau took a significant hit, losing all the special stuff that Farsight Enclave had, but they did get some other new rules.
Eldar actually got stronger, and so did dark eldar.
Grey Knights and Thousand Suns, and Elysian drop troops got utterly fucking destroyed this edition. In all but 1 instance, every single change they have made to the game has made these 3 armies worse.
Space Wolves and Blood Angels are in a good place so far, but dark angels lost some of their snowflake jank bullshit.
Tyranids got better, like a lot better to the point that nearly every unit in their army is viable now.
Imperial Guard have been stupid strong all edition.