I'd love to see that back because it would give one the opportunity to play against like minded people without having to use extra stuff like websites or apps to keep track of the league/cup. I think it would be somewhat of a success as I know of at least 3 communities playing private tournaments and either way I think it's sorely needed with the state of the current setup of online gaming.
But again, if Konami don't have a way to monetize it they don't see it as being in their interest to spend ressources on it. If they did it they would probably charge for it in some way...
That was in PES11 and it was a-w-e-s-o-m-e
Not only did it keep track of the fixtures, the order in which the fixtures have to be played in....it also recorded the cards and suspensions. And the most important of all, accumulated fatigue! So all the teams who play crazy press gotta actually rest their players from time to time.
Even with all of us who play leagues now using websites and apps, it'd still be good to have that online community league mode back.