Well it isn't harder to me. But it's at least done a different approach with the mechanics which seems to wipe out whole alliances occasionally. Which is something I at least want to see from such a raid. And of course you're right that in 7.5 it will be like Labyrinth or Void Ark. An actual striking dummy because they don't tier sync it.
It has a Doom cast?
I agree because rotations were more punishing before with factors like ranged attacks breaking combos, combos expiring if not continued for a few seconds and also the better telegraphs are a factor that makes things easier now.
Although I do think some of the mechanics from the past area easier purely because they added them to dungeons in a lighter form, so that now your average MSQ player is used to them if they see them in a raid. Hall of the Novice is probably another factor as well.
There was also just more responsibility in those raids that they seem unwilling to return to in the casual version of Alliance Raids so far, such as placing things permanently (like webs), needing to separate bosses to prevent them tethering, a majority of people needing to be on pads (people complain about towers in the Chaos raid, but it worked in the unnerfed Thunder God fight by only needing to be done by 60% of players).
Sure people got "stuck" on Ozma and Thunder God in past alliance raids, but I don't see a problem with this at all because they try again and eventually beat it, or some alliances would clear at least. It's only a problem if hardly anyone is clearing. When they were current, I hardly saw any actual abandons - rather, when the person complaining we weren't good left and was replaced, we would suddenly clear it.
It's ironic how that works. Whenever the person complaining the alliance is bad got replaced, suddenly it was a clear.

There is also an element of emotional communication. We're all there doing it together, communicating with character movements or macros as well. Which is in contrast to, say, Island Sanctuary where you are completely alone and don't even have so much as that.