Obviously you have yet to play FFXI. As for a plot, it has one, it's not as deep as past games, but still entertaining and there none the less. And of course way better than any plot other online games attempt. The plot though, get's developed by doing the different missions of the game, at first the missions (some of the early ones at least) are kind of uninvolving to the plot, but as you hit mission 6 the start of the over all plot begins and as you progress after mission 6 the plot get's deeper and deeper. Personally I have yet to get that far in the missions, I'm only up to 7, but so far the plot seems to be getting nice.

As for the game going back to the class system. I like it, it's way better than any other system they might of tried. Sure it has some down points, but what system doesn't? Besides the class system in FFXI beats most other class systems in other game, in this one your ALLOWED to switch classes as you wish, in most other online games you have to delete your guy and start a new one if you want to play/try a new class.