But I'll make a couple of guesses. I think they need to go for a lot more human input. It goes against the grain of everything they do, they want to solve everything algorithmically. But SEO is just too good at abusing algorithms. I think they need to get more humans involved, and force the SEO guys to tone it down.
And one tiny specific suggestion: drop the strong signal of a search term being in the domain name. Maybe leave it for proper names, but drop it for all generic words, please. It used to be a good signal. It used to be that when you saw your search echoed in the domain name, you knew you found what you wanted. Now, I cuss and skip it, because I know it's spam. It's been abused beyond belief.
EDIT: Yes, lots of people suggest "going social" on the problem. That's a lot harder for most people to manage than just using a search box. And searching for "trusted social group for reviews" is just going to take you to mytrustedsocialgroupforreviews.com. Guess what's there.