The combination of the twin Matisse I/O dies (one on the CPU package, one serving as the X570 chipset), Zen 3 chiplets, and overall maturity of the AM4 platform is still unmatched. I'm waiting for AM5 to "get good" before upgrading my 5950X (even though Zen 4 and Zen 5 chiplets are already quite good). I hope the next gen brings a core count bump, better DDR5 stability at higher speeds in 2DPC configurations, and USB4V2.
Certainly agree on the chipset front - I went from an X570 to B650 which was absolutely a downgrade, the most painful being the loss of ACS on the chipset PCIe lanes.
Terrible for VFIO!
ETA: Oh, and PCIe Gen5 between the CPU and south bridge(s).