#1 Not a successful hero in the past
This may not be the first time when we're watching Miz as a fan favorite - he turned face back in 2013. The WWE Universe had been craving for him to freshen up his character and have a babyface run. but when he did, things didn't turn out to be AWESOME!
His feuds with the likes of Cesaro failed to capture any sort of attention as The Awesome One was often welcomed with a pretty tepid reaction. Fast forward to 2019, we have Michael Mizanin reverted to a heroic role.
Miz and Shane's feud unfolded in a rather shocking manner, and while the WWE Universe expected Miz to be the one who breaks the bond, it was Shane-o-Mac who back-stabbed his partner and even assaulted his father.
WWE may be planning Miz's current character arc to run for some time, but WWE enthusiasts are well aware that things didn't turn out to be particularly remarkable the last time around, and it would bode well for all parties involved if we get the heel Miz back.