I don't think gmail filtering got worse, I thing the spammers got better. But - yes. Looks like the spammers varies the characteristics of their email's every single day. Worse yet, most of them are phishing not just spam. I have bee reporting then as phishing over and over and over and over.
Confirmed, but it's not only google. Especially the phishing letters, Actually seeing obvious phishing messages, but the DKIM records are validating, and several other anti-spam measures are being bypassed.