>>Google tends to let down users who are looking for expert answers.
Yes and no. If you actually are an expert, you can probably craft your search to get expert answers and you start to leave signs, which Google will eventually notice, that yo are an expert and don't want superficial answers. The problem is when you are searching outside your area of expertise (in my very subjective and non-scientific experience). In any new area, you as the searcher go through a set of iterations as you hunt for the right level with your questions. It's like dropping depth charges on submarines.
That said, I do think that if you linger on a set of "expert" pages and then come back for another round of searching, you get more expert answers (again, super subjective and not something I've tried to research)
>>deliberately serving results to match a multitude of these interpretations rather than the 10 closest keyword matches.
Again, this is really, really subjective, but I think search results are getting more and more personalized and less and less keyword dependent. Of course, we all know that because it's been happening for years. But there are some things I've noticed lately that seem more prevalent in the last year or so
1. Synonym highlighting in SERPS. Now I see terms that many humans would not recognize as synonyms treated to the bold highlight and I feel like that breath of those terms has expanded a lot lately (post Rankbrain?). Most of us here remember when it felt like a big change when it was no longer worth optimizing for plural vs singular. Yesterday I searched on "plans historiques de Geneve" and "cartes historiques de Geneve" and the search results were identical and the bolded search terms were identical. I saw a more extreme example a couple of days ago to the point that I called Theresa over to look... but I forget the search terms.
Conclusion: "keywords" as we knew them 10 years ago are dead.
2. Autocomplete is getting better and pushing people to certain searches, but not in the way it once did. Now autocomplete has full spell correction on the fly and is personalized based on your searching habits. Again, I feel like this has changed a lot lately. Yesterday, I read an article on sound isolating versus noise cancelling headphones while trying to find some bluetooth headphones for my dad. My next search, I typed in "best sojund i" (sojund with a J). As soon as I typed the "i" Google suggested "best sound isolating headphones" as a search query.
In other words, the only word in that search that old "keyword" Google would have recognized is "best." But based on my recent search behavior, new, smarter Google knew my intent as a searcher.
Conclusion: "keywords" as we knew them 10 years ago are dead.
Honestly, I don't watch this sort of thing like you guys, so that's all probably painfully obvious. But I suppose that's the point. Even I see this just in daily use, without really studying the SERPs.