An Upgrade, lack of depth, a new face all these words would be true to describe the impact that a new team would have in the WWE Tag Team Division. The Motor City Machine Guns could be that team as the WWE maybe interested in bringing the former TNA Tag Champions in as a fresh team for NXT when the territory begins to tour. Much like a lot of recent signings WWE has made they could help both NXT and the Main roster.
I do think that in terms the injury history that Chris Sabin has it maybe better for MCMG to be in NXT were the investment is lower and the depth is higher then being on the main roster. If you have seen my WWE 2015 Let's Play then you'd know that I am a fan of the Guns as I signed them with WWE for the Main roster division.
The feeling that NXT needs more experienced stars to be able to draw when they start touring in my opinion false, because let's put it this way Jushin Liger didn't sell out Barclay's Center for NXT: Brooklyn it was the talent that is down their that sold out the arena. That doesn't mean new faces wouldn't benefit them, but I just think Shelley and Sabin would be better off on the Main Roster then NXT as the Main Roster is in need of some new teams when NXT has other ways to find new teams.