The change was definitely palpable after the talent tree update. There was a period there where I wasn’t quite eking the full potential out of my build (zealot kept getting nerfed too) and was not yet used to 20 gunners or ragers spawning in at once.
It seems to me that after the power increase they had to scale the game difficulty to match. Of course, they have the issue that it has to be a challenge to those with well-chosen and -designed builds but not be utterly insurmountable to those with poor builds which is quite a stretch given the amount of power builds now convey, but it is also speculated they ran into an entity number issue.
Previously, combat was primarily horde and mobs with very occasional scattered elites and small waves of specials on their separate timer. If you recall, it took real effort to get 3 elites in one spot for the psyker self-splosion challenge. I only got it with the team effort of two shield ogryns shoving 2 shotgunners while waiting for the next one to spawn. The challenge for ogryn to knock over 6 enemy ogryns often took a zealot to run through the first half of the map and aggro all the ambients he could in the hope that there MIGHT be 6 ogryns among them (then die and let them go back to the ogryn player camping a choke-point). And there usually weren’t. When they added crusher patrols it became trivial.
The theory has widely been that the deciding factor here was cross-play. Because of console limitations on number of entities, they had to compensate by somewhat reducing the number of units but have high threat units constitute a higher portion of entities in play at any given time. Ergo the gunner/rager spam parades. If you recall, crossplay was rolled out at the same time as the rework (Oct 2023) so a lot was happening all at once. (In fact, that may have just been the X-box launch, no?)
I guess it’s two different types of gameplay and it’s definitely not the worst thing they could have done but a part of me does miss the non-stop pox hordes of the old days and the worst enemy in the game being the humble shooter.