I understood why they continued to have season after season, but they've really shot themselves in the foot with how many Rookies have come through NXT, have been put on the main roster but just have nothing going for them whatsoever.
The only success storys have been Wade Barrett and Daniel Bryan, but you could even throw David Otunga in there just because he has actually been used frequently ever since Season One ended. He may not be that flash in the ring, but he is improving. Also, the future is looking bright for Skip Sheffield, Brodus Clay and Alex Riley (even if he's currently in the doghouse) as the WWE seems keen to do something with all three. Percy Watson & Titus O'Neil make a good tag team but are stuck on NXT, and anybody else just doesn't have much going for them or has been released.
Justin Gabriel & Heath Slater are rarely used on Smackdown, Michael McGillicutty is only used on Superstars, Derrick Bateman & Johnny Curtis are NXT mainstays, Darren Young has been suspended already, Husky Harris, Eli Cottonwood, Byron Saxton & Conor O'Brian are stuck in FCW, and Michael Tarver, Kaval, Lucky Cannon & Jacob Novak have been released. Guys like Harris, Gabriel and McGillicutty have all shown something to me, but are being given zero.
More seasons of NXT are just going to add to this, even though they have some really talented guys coming through.