I'm hoping they continue and expand on the UB subplot in Gen 8, maybe make it so the plot kicks off just before the first Gym leader but really kicks off after said Gym Leader, afterwards it happens concurrently with the main plot with more and more UBs becoming available overtime, alongside the option to travel to each of their worlds (unless some of them share a world of course). I would also make it so that the no. of UBs increases from 11 to 49.
also the researcher in charge of the study of the UBs doubles as the 8th Gym Leader and uses 2 UBs in his Gym Battle with you, he also owns a series of islands where UBs that are still wild but refuse to return to their home universe can live without becoming an invasive species
What about you guys and gals, do you wish for the UB subplot to continue in gen 8 and if so what would you like to see?