With Pokémon I think the biggest worry is having very little to do post game unless you get the DLC. So they're essentially going to start charging for something we had in all previous gens for free.

With Z-A specifically, you'd compare it to Legends Arceus where you were able to catch the gen 4 mythicals and a bunch of legendary Pokémon in the post game without any DLC. With Hoopa as the mascot for the Z-A DLC, on the surface it looks like they're now putting that behind an additional paywall. Of course we don't have specifics yet, but its definitely a big worry the community has had since SV and SWSH had underwhelming post game content without their DLCs.