Actually a VERY good point !!

I think the letter is a heavy handed and would focus on the humiliation the passenger faced, and how he was treated (were they nice about it or treat him like dirt or a criminal, etc). Also, it's about UA's employees having the authority to make a decision and how would you as a passenger know they have that authority after this experience so how could you ever trust what you're told after this experience of essentially being told by the rep B that rep A is clueless and wasn't allowed to do what they did.

Sorry it happened but a C ticket is a pretty good deal along with the freebie so I wouldn't focus that he wasn't compensated well. The OP didn't mention if that Y ticket had been upgraded on the original itinerary or not .. if not, this was still an excellent deal for the OP but I can understand the bad taste it left in his mouth