No one is really saying FFXI parties were incredibly fun or brilliant. All the opposite, but they were STILL more entertaining than leves, which are perhaps the worst type of content i have ever seen in a mmorpg. Party dynamics were much more relaxing, leveling up was much more important, you always played with other 5 people and the monsters were capable of killing any of you in less than a minute singularly... it's a combination of factors, really.
And yes, when there is more content leves won't be as annoying, but they added sidequests and those are just the same as leves. Wonder what's with that. When will we see engaging content at last?