XP is much less per hour now (which I think is a good thing) but honestly no one in my linkshell has been having issues with partying. Just cannot go crazy and pulling 9 mobs at once like before and get 20k xp/6mins. 60-70k/hr seems to be about average give or take 10k. Honestly Rank 40 leves and Partys seems to be about equal SP per hour now in groups. Leves below 40 non-leve groups seems to pull ahead easy.

As for the multiple tank I suggest bringing them if you have 8 ppl. 2 healers, 2 tanks, 4 dd and things will go smoothly. The XI 1 tank mentality needs to be broken with the link system currently in place, it is doable but alot harder and more stress on healers and tanks then it should be.