Hmm. I hate to throw water on this. I read about FANTASMIC when it was only in DL, and really looked forward to seeing it in MK.
BUT, if you have to wait in line 45 minutes and sit in your seats for an hour (sometimes getting some good pre-show entertainment, sometimes not) for a 25 minute show that is (let's admit it) 50% films projected on screens made of water sprays, you might have second thoughts.
We have always come in late, got seats at the last moment, way over on the left, standing room once, and ALWAYS thoroughly enjoyed it. (The key was we always brought new people with us who had never seen it.) I am sure that the extra hour and 45 minutes would have detracted substantially from our enjoyment. I notice that the dinner packages DO NOT guarantee center seating (not that it is necessary) but do not really even guarantee good seating within their little area. Unless you get their early. So what's the point of an expensive dinner?
We caught the FANTASMIC at DL a few yars ago: it is relatively small scale, in terms of audience, (but not in terms of show) and we came in late and had to watch what we could see over peoples' heads. It's done on Tom Sawyer's Island and you just have to be on the walkways of Frontierland and New Orleans Square to see it. No huge stadium. Quite fascinating. When the big pirate ship (instead of the steamboat) came careening around the corner, I had forgotten that that was one of DL's big boats. A great effect. Plus that the Peter Pan theme is more included in the DL version of the show.
A nice show, but not worth 3 hours investment of time.