That hard mode was stupidly easy, we wiped once on the last boss only cause we wasn't ready for the change and that was it. Done in under an hour, and we finished the death zamboni in 4mins:30seconds~. Noticed the mobs didn't go above 390 and the changes were all pretty tame.
I actually think the HM change on the Siege Engine helped us in a way because it forced us to slow down for a minute. Where as before you would sometimes get people charging ahead with parts when there was still too many adds around.