There is a fear among people internally that once NXT begins broadcasting on the network that the style it showcases will have to change to meet that of the one seen on main roster television. It's no secret that in NXT, the guys have more freedom to do what they want. It's their creative outlet to hone their skills and improve before being promoted, if their promoted at all. See: Chris Hero. But with the show moving to the network WWE might not want fans becoming accustomed to the development territory and viewing it as better than what is found on their televised shows.
Truth is, when it comes down to it, the people who watch NXT are the Internet fans. A casual fan doesn't know what NXT is, if they do they probably don't care, because it doesn't have the glamour of Raw or Smackdown. NXT is the hidden secret for WWE's universe because it's something completely different to what you get on television. It's WWE's independent territory of sorts, and it going to the network, is like that independent territory being bought.
NXT can be a great show and has produced some great matches such as the Zayn and Cesaro match in late 2013. It allows guys like Bo Dallas, who fans hated early last year to find his feet in the WWE. Does that mean It'll translate well to main roster television? That's the new fear. Their currently running vignettes hyping Alexander Rusev and Lana. Rusev was over in Full Sail because he squashed someone during every taping. Being over in Full Sail is like Chris Hero being over in ROH or PWG. It means about as much in the eyes of WWE. If it doesn't translate well to television, then it's right back to Florida for some more tweaking until they hit the right chord or someone gives up. Again see: Chris Hero.
For someone like Rusev, if he were to hypothetically fail on television, he doesn't have many places to go beyond WWE. That's why we're not going to see too many more independent guys signed up, because if they fail and leave, once they go back to the indy circuit like Chris Hero has, their stock rises, and WWE doesn't want that to happen. With less independent guys being signed you'll slowly see that free style diminish, especially once the likes of Zayn get promoted to television.
The NXT: Arrival show will be very interesting because it could be either the end of how NXT is currently shown or the beginning of how WWE plans to show it. They don't want people tuning into the network to watch NXT and see that the quality is higher than their television shows. To ironically use that phrase we hear so much, it's not good for business and it makes the main roster guys like Cena, Orton, Sheamus and others look bad, because fans will take the more independent influenced style NXT has over what the main roster guys can do.