Fraught with dangers even though there are pros and cons.
NATO and specially US will get a foothold on Gwadar, right at the mouth of Chahbahar Iran, Iran will also oppose it.
The pros for Pakistan seems to be CPEC and Gwadar will get more importance for US and hence more legitimacy and approval ratings from US. A supply route from Gwadar will make that happen but entails lots of clear and present dangers.
The cons are again the malafide intents and interests of US vis-a-vis Balochistan, not manifested clearly and is hidden, espionage and spying network starting is not far fetched, Kulbashan J is a case in point.
The US once embedded in Gwadar will run the risk of China having problems with their greater expansion plans about the Gwadar port, a naval base here or nearby, blue water navy and the CPEC as a whole having left open to the US, NATO is a lesser entity here, it is about US.