Apart from KDB isn't a far superior player. Currently more effective and important at a smaller club yes, but I'd say PP has greater potential.
Why? KBD absolutely destroys Bayern every time his 'smaller club' plays them; Pogba is brilliant against pub teams like Chievo and Empoli. Wolfsburg would give Juve a run of their money in Serie A.
In what way does Pogba's potential eclipse De Bruyne's? The few games he's played in central midfield, KDB dictated the tempo of the game like a Modric/Verratti type, while Pogba's passing is average at best. He's more creative, scores more. More tactically versatile, more mobile.