I don't know how the crowds normally work for this. It turns out that the week we were there (March 24-28th) was the busiest on record for DL. So when we went to Aladdin with our preferred seating tickets, we saw the people lining up for the 12:25 show at 11:15. That turned out to be the preferred seating crowd. They took your tickets at the front box office area, and put you in a covered area on the side of the building to wait. It looked to me as though we wouldn't have had to line up so early, people who came much later still got in and got great seats on the orchestra (floor) area. We had seventh row center, very nice seats.
That said, it is TRUE-- mezzanine would have been better, especially if you could get in the first couple of rows. For the two scenes you mentioned, it was hard to see anything (especially the carpet). But, on that very busy day, people lined up at 11:15 and waited over an hour, and unlike the preferred seating people, they waited in direct sunlight.
I suspect it's not so dire usually. That was a very packed park.