If Mullah wasn't the VC, would they change the XI for him? No! I don't see any reason to drop a top order batsman to bring in a middle order. I don't like Imrul, but unless we are bringing in a PROPER opener, I don't find any reason to drop him.
To send out a message, selectors shouldn't pick Riyad. And the message is whether you are a captain or a vice captain or THE Ashraptain, your spot is not guaranteed.