Update: Just installed Android April update. Haven't done any speed test yet but, using WiFi Overview 360, dBm on LG G4 -29, dBm on Pixel C from same location ( both 5G) -42. G4 seeing 7 networks on 2.4, Pixel C seeing 2.
Need to do further tests but doesn't look like Google have improved WiFi in any way.
Still no problem for me as I use mine on 5G around house only but not looking good for anyone relying on weak public networks.