Dawntrail currently has the best group combat content I've seen in any MMO, with no competition (EX1, EX2, Arcadion)
I started playing MMOs all the way back during the early 2000s fever of Korean MMOs. Played multiple ones afterwards, both eastern and western and eventually obviously played, raided and parsed a famous MMO in the industry for many years, sometimes even went in blind. Dawntrail currently sits at the top of all those experiences for group content, with no competition.
Progged and cleared EX1 and EX2 fully blind
After doing EX1 and EX2, I felt like it's been many years since I had *last* been incentivized by some mechanic structure to want to perfect the fight by not being hit by anything.
Likewise, another mechanic structure makes me want to min-max my DPS a lot and really want to not die. It felt very satisfying to be able to grow over the fight, solving mechanic after mechanic (went in blind on both extremes) even if it took a while on some, but when I felt like I was in the flow it felt very satisfying to feel myself in that state.
I walked out of those fights looking forward to farming them and improving my performance so I can get a clean clear and start parsing properly, I finished Extreme 2 wanting to do it again and wanting to talk about it with people, wanting to see others doing it on videos.
That's not something I easily felt before. The content must be in a really good spot to trigger that, with good readability, consistency and a rewarding sensation when you surpass them.
The mechanics are honest
Very few "gotchas". The mechanics are honest, with clear tells. I might not understand them on first pass, and might even take a while to be able to solve them on my own, but when I finally get there it feels immensely satisfying.
Previous FFXIV expansions had mechanics where the tells were hard to read, or there was a "gotcha" in them that you could only learn through repetition because nothing indicated there was a twist on the mechanic. There are some such cases in Dawntrail, like the Barreltender's aoe that increases in size in a way that you can't expect, but they are very rare, and less present than in the past.
Boss body tells were also something that felt harder for me to read in previous expansions, and that seems to be way better executed in Dawntrail.