This is a case of the old adage 'You can please some of the people some of the time, but you can't please all of the people all of the time.' Or 'Different strokes for different folks.'
A lot of divers don't like being assigned to an 'instabuddy,' to the point the term at times on SB carries a negative connotation. Many divers appear content doing the 'group follows the guide' dives, with the understanding that if someone has a problem they can approach the guide or another diver (e.g.: out of air emergency) - contrary to what some may say, this isn't the same as true solo diving.
So there are the polar opposites -'I should always dive with a buddy!' vs. 'Lemme alone!,' and shades of gray in between. A dive op. that does what you suggest (assigning buddies) will annoy and push away some customers.