I’ve spent too much time thinking about this for my own good - but I think this is the crux of the problem with legend feeling much harder. It’s not the changes to the combat mechanics that make it harder - it’s changes to the AI director ramping up the level of chaos that is possible.
The thing is, specials typically spawn in a few waves (and in pairs on legend) right before and during the waves of a horde. The numbers of specials HAVE been increased over the old legend. In addition, you also have horde waves mixing in elites - SV’s, monks, maulers, etc. So you frequently have a situation of needing to CC the trash while dealing with high damage armored guys mixed in (and trying to dodge their crippling attacks) - and then all of a sudden you get two gutter runners or double globadiers.
The presence of elites mixed into hordes compounds the difficulty of dealing with the specials during the horde because with the elites in your face it’s much harder to make space to safely kill the specials at range. Even if a teammate gets downed nearby to a hit or disabler, it’s much harder to rez them when there are multiple elites combined with range specials that break your block and interrupt the rez. In my experience, this is where the wipes happen despite seemingly good play and teamwork.
All of the above issues are MAGNIFIED immensely when it’s beastmen during the horde. The sheer size of gors makes it very difficult to see, let alone shoot through, the meatwall to kill specials. Moreover, the beastmen are quite tough and harder to CC than other enemies, so creating the space to take out specials at range is made even harder.
One recourse is being far more strategic (and communicative with your team) about where you are engaging and holding off a horde. You need space to maneuver and fall back in case of a gas rat bombardment. If a gunner shows up you need to be able to retreat around a corner and get out of line of sight. Ranged characters need to have some space to work and take out specials, with room to dodge random mobs that slip through the line. You still want to limit the angles of approach so you can better CC the hyperdense mobs, etc.
In short, position, position, position is the name of the game.
This adds a much greater burden onto legend if you want to be successful, which is a notable shift from pre WoM where dodge dancing meant you really didn’t need to think about positioning much at all once you mastered the basic dodge dance routine. With dodge dancing, team cohesion wasn’t really necessary at all. It now is.
EDIT: I’ve only had a small number of legend runs since WoM where the team played like a team. Even one person thinking about positioning that says “come here” can make a difference to getting the team grouped up. The runs where I had a solid team, we breezed through legend. When you don’t have that, it’s a total gamble with very low odds of success (below 10% in my experience).