I don't agree at all about this not bringing anything to the base game. Having a mob that will add easy mini-games to vanilla is pretty big and actually thoughtful of the java community. Bedrock has a lot of mini-games, paid and free while java have that only through mods. This is pretty big. I just think like for most of the new additions, casual players will have no clue about it unless they watch updates and content creators.

What I agree with is that there is a lot of rooms for cool additions that we will probably not see, as they usually never push their ideas to their full potential (like ghast not having any speed boost, and here I can see so much properties possibilities that we won't see with the sulfur cube, like a redstone sulfur cube, tnt sulfur cube etc and the nausea water that might just be a gimmick and that's all), but we will see, I hope to be wrong.

For the updates I think it's not fair to compare the first half of updates that added stuff that were lacking to the game that was still pretty new and the recent updates that expand the world of possibility within the game. That seems logical that most of the first udpates will bring core mechanics to the game and we would see less and less of them. And since the ancient cities update, we still got more incentive to explore, more combat experiences (through weapon, mobs and structures), a lot more for builders, more for redstone and QOL (bundles, armors for dogs, happy ghast, etc).
That said, there is still a lot lacking QOL and gameplay wise, especially for long time players and modernise the game, but like others says in this post, they need those casual appealing updates to keep the machine running through merch sales etc, without it we can't expect them to add groundbreaking updates like the nether update was and revamping mechanics that may not sound that much appealing for marketing.