I tried the 4.8.4 last week just before it was pulled. Yes the WiFi signal strength was worse but the throughput on WiFi was the killer for me. In my bedroom I went from a solid 600mbps to 40mbps.
I’m staying on 4.8.3 unless the throughput of future firmwares matches it.
Was only able to upgrade to Fibre this month and that firmware made me instantly go back to copper line speeds through WIFI.