I understand your dilemma. We have stayed at both resorts, so here's my insite to them.
Like you, we looked at Coronado Springs and felt it was a very beautiful, interesting place. So we booked, just hubby and me, and it was a beautiful place. We stayed in cabana bldg. 3 and the courtyard was beautiful with a lovely fountain, tropical plants. The rooms were spacious and clean. However, we felt it was too large for us. Our cabana was closest to the main bldg. and it was quite a trek to it. We were not fans of their Peppermill food court. Maybe it has changed, but it was too complicated a place for us. You would order at various stations and get receipts at each which the waitress had to figure out. It was never an easy in and out type of place for us. I have heard it is changed for the better now though. Never used the pools, but the main pool was Way across the lake from us anyway.
Then we stayed at POR and loved it. We stay close to the main bldg. We love Alligator Bayou because of it's secluded walkways, bridges, tropical atmosphere, quiet pools, boat to DS, and their great food court. For your son, the arcade is the largest in WDW. There are carriage rides available too, and bikes to rent.
I don't agree with your TA trying to persuade you for and against Coronado. It all depends on what it is that YOU want to experience. Both resorts are beautiful.
As a side note, we never encountered any drunken, unruly guests while at Coronado. Never could tell it was even a convention hotel at all. The rooms were probably nicer because of that? Good luck and have fun