Heh. Here I was, expecting this to be about the actual format of the various leagues, how the tournament itself was set up. And here I was, ready to expound on how Sinnoh's league had about the least inspiring setup so far (the only thing setting it apart being the much smaller number of competitors).
On that note, though, I do think I like Johto's tournament layout best--while it undoubtedly had the biggest drop-off (hundreds down to forty-eight), at least it gave every applicant three chances to battle (as opposed to the at-most two chances a quarter of every other tourney's competitors get).
And further on that note--I actually was hoping Sinnoh's tourney would be set up this way--but I still have some hope for a tournament whose qualifying rounds are based on...well, chance. The field type, the match type (1-on-1 singles, 2-on-2 doubles, 3-on-3 singles, or 4-on-4 doubles), and perhaps to an extent the pokemon chosen for the battle--all chosen completely at random right before the match begins. You know, to give each person a chance to show how they cope with totally unexpected situations.
But that's apparently not what this thread is about.
Given the apparent faster pace it seems we'll be getting this time around, it only makes sense for there to be an interlude saga following the league; how quickly Ash completes his journey around Isshu doesn't affect how long it's going to take for the sixth generation games to come out, after all. As such, not only would a league dedicated pretty much solely to the Isshu captures be ideal, I think it's what we should expect. Let the old guys show up afterward, when they're not as likely to sap precious screentime away from the current generation.