Honestly to keep the show interesting, and less like a joke they should first do the following. Right now there are just too many stars for the show NXT. Perhaps change the total amount of stars to 4? Next, the move would have to be changing the length of time in between the eliminations, and basically lengthen that time. The fans have to get familiar with these guys, and combining less stars with more time in between eliminations could help.
I would even go as far as to having stars from other NXT seasons coming in as opponents for particular match types that may, or may not favor either wrestler. Just because these old NXT stars didn't win doesn't mean they don't have the right to show themselves again. This would be interesting to see how the fans react to these old characters who tried to win them over before.
Finally, get rid of the horrible obstacle course nonsense. It has no place in wrestling, and for the most part keep the show based on just wrestling, and promo work. I liked the impromptu promo competitions that they had. Provide a little more in depth look in to all the characters, so that fans have that much more to connect with.