One of the main complaints about the original PS4 model is the lack of 5 GHz support by the console’s Wi-Fi module. This appears to have been changed for the PS4 slim according to Twitter user shortman82, who purchased one of the leaked units.
Shortman just posted on Twitter a picture of the manual that indeed indicates 5 GHz support and one of the console’s UI. While the “Wi-Fi frequency band in use” option says 2.4 GHz, because that’s what Shortman is using, the option isn’t present at all in the original model, which also appears to confirm support for different bands.
While we should wait for an official confirmation before rejoicing, this is definitely a good sign.