Not sure wheter or not they would bring him back for an entire season. Sure he's one of the main chars, but he's been around for most of the series and I feel some fresh companions would be pretty good.Maybe May but not Max. He needs to be forgotten.
And I hope that for the next season they bring Brock back. Just say he is doing a field study or something like that. He is too good of a character to not be around anymore.
Even tho so far, atleast for XY, it feels like Serena and Citron just split up the role Brock had in the older seasons.
I wouldn't really mind seeing him again, but I feel it's unlikely.