This is the deal. I believe that Just Blaze and Nottz are the 2 most talented producers on earth. I'll even say top 3 just to consider the option of someone that I don't know about. I also know that this was not a battle, and they just did it for the fans.
I also think Alchemist knew that Just Blaze was playing entire songs with vocals. If he didn't know, I don't think he cared, since it wasn't a battle, and they were having fun. I say all that to say I would have rather heard Just Blaze rock out with the pure instrumentals.
I gotta give this one to Al. The way he closed out was strong.