If any of the gym leaders return it should be the Kanto or Johto ones. Particularly the Kanto ones. They didn't get **** in their own saga. Misty, Brock or Gary appearances could be possible as well as a possible debut for Janine or an Elite 4 member who hasn't debuted yet (Will, Sidney, Glacia, etc)
Of course they're not all going to appear. I'm still hoping for eight new Unova gym leaders in BW2 so that Ash can challenge the Unova League twice. N and Team Plasma's intervention in the League could be a plot device to make Ash wish to challenge the Unova League a second time. Maybe he'll feel that there's still unfinished business with Trip and his other rivals. In this hypothetical filler arc I'd like to see Team Plasma's storyline pick up right where the League leaves it. Possibly focusing on their plot from BW2 rather than the first games. Ash vs Homika, Shisui and Cheren along with the other (hopefully) five new gym leaders. I do think there should be at least two more new gym leaders introduced though... If Chili, Cress and Cilan are all being done away with and there's going to be a new Water type gym leader that leaves room for a new Grass and Fie type gym leader too. Darmanitan seems like something that would make a worthy boss battle in the games. And I can just see some elderly, poofy-haired gardener women and her Whimsicott as one of the gym leaders. And this may just be me hoping for a Dark type gym leader since I've wanted one after Gen. 3 but Zoroark would be another excellent boss battle. There have always been more than eight gym leaders per region in the anime anyway, its not like that's something new.
Perfect scenario:
Ash vs Drayden(Ash wins)
League:
- Ash defeats a couple of weaker opponents
- Maybe Ash defeats Binaca or Stephan here. Which ever he beats, he won't face in the next league
- Similar to Gary, Trip loses before facing Ash to a mysterious trainer named N with a legendary pokemon
- Ash loses to N in the next match, N goes on to win the League.
- With N's victory, Team Plasma storms into the stadium and demands that all the losers release all of their pokemon this leads into the first Team Plasma 2-parter
Unova pt. 2:
- Team Plasma is defeated near the end of the saga
Gyms:
- Ash vs Steel type gym leader
- Ash vs Homika
- Ash vs grass type GL
-Ash vs Fire type GL
- Ash vs Shisui
- Ash vs Rock type GL
- Ash vs Dark type GL
- Ash vs Cheren
League:
- Ash vs Bianca/Stephan
- Ash vs Trip
- Ash vs trainer who defeats him
So the first league can be very much like the Hoenn League. Short but sweet battles between Ash and trainers that aren't recurring and with Ash only using pokemon from the region he's currently in. The second League can be like the Sinnoh League with longer battles against Ash's main rivals, use of reserves and no focus on CotDs
*cries*.
