#3. Call ups were relatively meaningless
Let's be honest here.
Although seeing DIY team up against The Revival, Ricochet team up with Finn Balor and Aleister Black take on Elias, were all great matchups, they didn't have any story built around them at all. WWE was also vague on whether any of these call ups will be permanent, which also diminishes the value of what WWE did.
Again, the idea wasn't bad in theory, in fact, WWE could have centered an overarching narrative around the debuts for good measure, but they decided not to and it really took away from what these debuts could have been. Think about it! Who had the more effective debut? The Shield at Survivor Series or Aleister Black, DIY, and Ricochet on Raw and Smackdown Live.
In the end, The Shield's debut had more of an impact. It protected CM Punk's title reign, it protected Ryback in defeat and it established The Shield as badasses right off the bat. As for the NXT call ups, WWE putting Ricochet and Finn Balor together was interesting, but they didn't capitalize in the same ways with DIY and Aleister Black.