Shifting the topic is a good idea, and I might as well start with some aspects that, while unlikely to appear, would be greatly appreciated. For instance, trainer nicknaming their Pkm (not counting trade Pkm!). Of course, not all of them should, but I imagine that if we were in the world of Pkm, at least there should be some people who love their Pkm that much to give them another name but their own. This could illustrate the bond between trainer and Pkm and also lead to hilarious moments. Ever fought against someone who nicknamed their Ferroseed "Hug me :["? That could be touched upon.
And while I'm at it, I might as well talk about evolutions. If I recall right, trainer start using more evolved Pkm after a certain amount of progress. While this is completely understandable - after all, evolved Pkm are stronger than their pre-evolution - I'd still like to see more unevolved Pkm, just like in the anime. To make up the loss of "power", GF could put these unevolved Pkm on a much more higher level than their evolution parts.
To give an example, trainer A has a Feraligatr on level 50 just like most of your Pkm. But he also has a Totodile on level 60. Power wise there isn't much of a difference between these two, I think. And GF could still invest in Totodile's HP instead of speed. If they want to, they could even give it Eviolite. Either way, this should make Totodile almost on part with Feraligatr.
Apart from that, I hope we'll see some buffs for Pkm who need them. This also goes for certain moves and abilities. I hope they'll still keep the new effect of Teleport. And maybe, this time we might see Queenly Majesty Vespiqueen. While I don't think it would improve her much, it, at least, makes sense for her to have it. She's a queen, after all! I'd also like to see Fur Coat Mareep. The ability could change when it evolves, but the point is if the Wooloo has Fur Coat, why shouldn't Mareep have it as well?
Another cool addition would be abilities like Forewarn and Anticipation. Why not making the Pkm immune to Entry Hazards? After all, they could sense that something's wrong on the field! Or what about Emergency Exit? It should give you the option to switch out as it's more in line with Golisopod's dex entry! Or give it, at least, another ability like Intimidate to make it even more bulky than it is or Shell Armor if GF don't want to make it to threatening. But then again, we have quite some powerful Pkm like Kartana, Margeana, Pheromosa, etc. Why not giving it Tough Claws? :DDD
I mean it would make so much sense and turn Golisopod into a very threatening revenger killer like Scizor.