Wireless charging itself does not directly degrade battery life, but a resulting temperature increase can. The longevity of a device's battery is affected by temperature.
Different battery chemistries react differently. Lead acids are more resilient than the now dominant li-ion batteries. The li-ion cells should be (and will be by any reputable manufacture) monitored for temperature. Charging systems often reduce or halt charging above certain thresholds.
Wireless charging typically causes additional heat due to electrical inefficiencies of both the wireless charging pad and the phone's receiving circuitry. I have personally observed my phones' reported battery temperature to rise in excess of 50°C (122°F). My older phones didn't even bother to warn me, and would eventually just shut down. Flashlight and WIFI are commonly disabled when phones are too hot. The later phones have given me a warning, and my S7 actually goes into some sort of "overheat" mode that disables most background processing in an attempt to mitigate shutting down.
Some wireless chargers have fans in them (especially the "quick charge" varieties that use more than the standard 5V input). One QI charger I have uses a fan to cool the pad's internal circuitry, but does not directly cool the phone at all (bummer).
To reiterate, wireless charging itself does not directly degrade battery life, but a resulting temperature increase can. This will depend on the charger and device being charged. It could be said that if the heat from the wireless charging is kept away from the battery cells, then the battery wouldn't notice the difference between QI and a direct plug in charge. This is not always the case, especially with small devices like phones. If the device stops charging to prevent over-heat, then the battery life is prolonged by an amount that depends on the over-heat threshold.