I will not deny that Dawntrail is challenging. The first dungeon is definitely a bit of a step up from the final Post-EW dungeons, and the trials are very much a new sense of difficulty.
However, I don't think that this is entirely on the devs. There are a lot of factors that make these new mechanics seem more difficult and unfair than they actually are.
First, it's new. By the time I write this, it will have been just over a month since DT hit early access. Many players are still going into the new DT dungeons and trials for the first time, or they haven't spent countless roulettes being forced to learn them. One of the big supports for burning my way through the main campaign over the past few months is that all the other players knew their way through the dungeons and trials, which meant that I could just follow their lead and not have too much trouble. Now, that's no longer an option.
Second, there is no denying that a decent amount of players are either new or returning after some time away, and instead of refreshing themselves in the EW dungeons and trials, they're jumping right into Dawntrail (possibly with a level and story skip) without having learned much of the mechanics that have been previously used. In essence, there's a good amount of people that are a bit rusty and still finding their way back into the flow.
And third, the approach to combat mechanics has taken more of a focus on evasion. Looking over the new boss mechanics in comparison to older ones, there is a definite increase in moments where having to stop attacking in order to evade chaotic mechanics is necessary. Up to EW, it was very rare that a melee DPS would have to fully stop attacking for more than a couple seconds in order to avoid a mechanic. In Dawntrail, there are now many mechanics that force the player into an evasive state, having to weave their way through a bunch of moving parts in order to not totally die. Everyone's favourite hive queen is the most notable case. Everyone's least favourite noggin man is the most severe and unintuitive case. All my homies hate Leonogg.
Beyond that particularly nasty fight, many of these mechanics are new to even veteran players, as they now have to take a new approach to dealing with fights as they can't just sit in melee range and run their rotation until some AOEs force them to back off. Now, players have to take their time and be a bit more methodical, whereas previously it was possible (and often encouraged) to just go bonkers until the boss died.
Anyway. At the end of the day, DT is definitely a new challenge, and that's not unintentional. And there's nothing wrong with struggling either! It's still new, and many players are still getting used to the new dungeons and mechanics. There's nothing wrong with taking vuln stacks, or needing to get raised a couple times because you got overwhelmed by a mechanic. And if someone does make you feel bad for that, then screw them!