In as general terms as possible. I was looking for a more engaging/complete post-game storyline.
In more specific terms:
Maybe have some of the characters from the main storyline appear for more closure to their arcs (most of which died around Ballonlea)
Have the fights more optimized towards players who have already beat the game as well (as I said don't just scale up the level of Avery's sole Abra, give him a more complete team if I've already beat the champion)
And since you say ideally. Not that I necessary expected it, but if I had a free Pokemon-DLC related wish, then 5 new Galarian forms altogether.
those are reasonable, and I can agree those were lacking. Honestly, one of my biggest criticisms of the scaling for both was that they made the DLC areas open to anyone the moment they hit the Wild Area. Imo, the rivals and the battles may have been received better if they were only given after beating Leon. Then they would not have to code either a poor team like we saw for postgame players ir 2+ teams per trainer for scaling.