I can only tell you what our experience had been.
We went twice to see Fantasmic on our last vacation, both times on the Fantasmic Package. The first time, we arrived about 45 mins to show at the front of the entrance. There was no line up, a few people were walking up with us. At the top, there was a CM standing on the right hand side taking the Fantasmic Tickets. She took ours and we asked her if we can get half of the ticket (in the past, they have always given us half of the ticket in case we went to the washroom and get some food), but now she said that we wouldn't need it. When we sat down, now about 35 mins to show, there were plenty of seats. 5-10 mins later, there was a whole crowd of people making their way over to the reserved seat from the general seating. At this point, they had opened it and there were no longer any CMs standing on the side. (This is why we didn't need the half of the tickets anymore.)
The second time we went, we arrived about 60 mins prior to the show, and found a lot of people walking towards the top, not necessarily a line, but definitely more than our previous experience going through this way. When we got to the top, again, they took the tickets and there were again, plenty of seats available until they opened it to the general seating.
I believe they must have let the people in a lot earlier than 60 min prior to the show. So, for those who have the fantasmic tickets, we don't necessarily have to line up, we just have to enter through the general entrance 60 mins prior to the show and we don't have to wait in line, although, we do have to wait in the seats.
I suppose, the advantage is still somewhat there. If you don't have the fantasmic package, they suggest that you line up no later than 1.5-2 hours prior to the show. With the package, you don't necessarily have to line up, you just go around 1 hour prior and by that time, most of the people have already moved in and you can go to the reserved area knowing that you have a seat.
I will admit they should have been more vocal about opening up the reserved section at 30 min before the show. And as I mentioned in my other post, they should communicate this to everyone who is booking the Fantasmic Package.