It used to be when they did Fantasmic every night, you could show up 45-60 min. before the show and get a seat, but the last couple of years they have drastically reduced the number of shows per week, so you very well may not get any seat at 45 minutes before show time without a dinner package ticket. During busy times of year, they do have multiple shows, sometimes even two a night. If you can go to the 2nd show of the night you have a better chance of getting a seat. The earlier show will always be far more crowded. If they add shows while you're there, they are expecting huge crowds (otherwise they would not add shows.) I'm not saying it's impossible to get a seat 45-60 minutes before show time, just saying you cannot be absolutely sure that will happen. We've been there when there were plenty of general public seats at 60 minutes, and it was slam-packed by 45 minutes ahead. We've also been there when they closed the entrance at 60 minutes before show time & had signs out on the street in front telling people it was full (we walked past the signs to the entrance for dinner package ticket-holders...and there will still plenty of reserved seats left.)
Even if you are going during a slow time of year...they will have only a couple of shows in a week so everyone who's there will cram into those two shows. We have gone to Fantasmic during very, very slow times of year (like mid-January) when wait time on Soarin' was 20 minutes, Test Track a Walk-on, Space Mountain a walk-on, Rockin'Roller Coaster a walk-on...you could get perfect viewing for MK fireworks and at-the-railing view of Illuminations 5 minutes before it started...yet Fantasmic was standing-room-only 60 minutes before the show started because though the crowds were light in the parks EVERY single person there had to fit into one of the only two shows that week (there was one on Sunday evening, and the other was on Thursday I believe.) So yes, the Fantasmic package seating is well worth it unless you want to get in line 90-120 minutes before the show to be sure you get a seat. If you show up without Fantasmic ticket at 45 minutes before show starts you may find theater is full and they're not letting in any more general public folks...or they may let you in, but show you to standing section...which unless you're really tall, you're not going to see much.. With the tickets, you still need to get to the theater 45 minutes before the show but the difference is you will get a seat for sure instead of standing-room-only space or getting turned away. If the place is packed, they will sometimes take down the reserved seat ropes 15 to 30 min. before show time and let the standing room people fill in the remaining empty seats in the reserved section, so you want to be sure you're in your reserved seat at least 30-45 minutes before showtime.
We liked Brown Derby...it's 2 credits on Dining plan, believe the cash price is around $46 per adult. We also like Mama Melrose for Fantasmic Package...that's cheaper (one credit on dining plan, or around $35 per adult.) Either one of those on the price fixe cash package or the Dining Plan package you get choice of appetizer, entree, dessert and non-alcohol beverage. You choose off the full menu, not a limited menu. You get the appetizer on the Fantasmic Package even if you're on the regular dining plan, it's an exception to the plan