I think's it's moreso that the Pokédex cut led people to start complaining about other issues that they were okay with before, especially after Game Freak specifically talked about how the cut was for reasons such as polish and making better animations. If you cut content and say it's because of better graphics, but your graphics are still shit, then people are either going to complain about the cut content or the graphics. Pretty obvious, really.
That said, I'm kinda glad all of this happened, because it made people finally realize many issues that have been plaguing Pokémon for years.
Pokémon missing didn't become known until weeks after the first trailer had been shown. I remember that I had watched the Direct and thought that Sword/Shield had decent graphics for a Pokémon game, but here on VGC there were quite a lot of comments about supposedly terrible graphics. Still, many people realized eventually that their own expectations were more at fault than the game.
When it became known that not all Pokémon would make the cut, the real bandwagoning for an anti-hype train started. The graphics have been more focused on again recently, because it turned out that there are still plenty of positive things to say about Sword/Shield, so the ongoing dismissive stance towards the latest Pokémon needed more justification than just the cut Pokémon and GameFreak's dumb statements in response to the cuts.
It's the same old story of a divisive build-up until a game's release where naysayers ultimately face the choice of either admitting that it was never as bad as they argued or doubling down by latching on to every little detail to justify themselves. Of course this same old story can also end with the apologists facing such a choice, but that isn't the case here.
As for the realisation of many issues, I don't think that matters much when even most of the naysayers will end up buying the game anyway, if they haven't bought it already.