mayby i've just played alot of games with 100 floor dungeons in end game (i just can quite you disgaea *cries*), but the concept of the fractals did sound good on paper:
a long dungeon what tests players skill and teamwork to complete 3 maps. it brings the group dynamic back to the game, in some cases it forces you to join a guild/form friends you can do the run with on regular basis.
their only misjudgement was that they didn't think how the "new stats" effected the community. if the stat boosted armor was given at level 80- 100 it wouldn'y be so daunting; (possible but i'm not going to grind 24 hours to do it)
but thats just my thought.