For me the most egregious way that Gmail is failing recently is that its search 100% sucks. It sucks in a way that's almost unimaginable. It uses fuzzy matching and single words when you use multiple terms.

I search "stock transfer" to find an email in my main mail from last week. It returns dozens of junk emails from my "updates" and "promotions" folders that just contain the words "share" ("share your recipes!") or "security" ("update your home security") or "inventory" (??).

Whatever happened to the promise of Gmail (I remember 2004) that folders and tagging were a thing of the past, that you could use the awesome power of Google to "just search" and the email you wanted would pop up? What happened to the Google that claimed to know whether your search for "bass" was for the fish or the guitar? Now it can't even tell that a search for "stock transfers" is not for "share your recipes?"

And yes, I know I can use quotes. Searching email shouldn't be something only the power users know how to do.