Technically 3 as far as the Quest log is concerned (roundabouts the same as the last Episode; i.e. the DM book in the Catacombs for the guy in Queous and the Fruitail from Soneros for the guy in Teddy Bear Oasis, plus Placebook... and nothing in Melonchi, I distracted everyone with the Minecarts to blind them from the sidequests! bwahahaha!).
Episode III has the composer in Portophus looking for the melody which you can pick up in Mideloneous and the cook in Kytar city looking for the ingredients, which you can pick up on the north part of the overworld, plus Flutter (don't forget to check it a few times... even after you meet Brodyn
Same number of dungeons, towns, and continents as Episode II as well. Weird. It's like I plan these things
Episode 4 will be really, really long. I'll say that now.
As for sidequests in general... after I finish up the final episode. I plan on piecing all of the episodes into one long game someday (I dunno, Arvale: Uber Edition?), complete with all of the latest features from the final episode and jam-packed to the gills with tons of extra side quests throughout the world (where you can travel back and forth between continents freely by a... well, you'll see one day
) Kytar city alone was just ripe with ideas (what's with those fortune-tellers anyway?). And that weird archery dude in Garga? Anyway, I think you get the idea :D