If all you want to see is FIREWORKS, you can stand at MOST areas in the MK.
(And a wide variety of places OUTSIDE the MK.)
But if you are NOT at CERTAIN SPECIFIC LOCATIONS, you will MISS the "full impact" of the SHOW called "Wishes".
Wishes has two fireworks "STAGES":
One fires its missiles from a location FAR BEHIND any public area of MK.
The other fires its missiles from the ROOF-TOPS of Fantasyland/Liberty Square/the Castle.
The guests' VIEWING ANGLE will affect "if and how" these two stages can be viewed together (they are designed to be viewed "together".)
There is a full AUDIO TRACK that is synchronized with the fireworks.
It is the "motivation" for the unique fireworks effects that change with each MOOD and SECTION of the audio track.
The audio, and positioning of the two fireworks "stages" relative to the viewer will affect the impact of the show.
The front of the CASTLE ITSELF is part of the "show".
There is an elaborate lighting system that is used to change the color of the castle to suit each MOOD, and even "textures" and shapes are projected on the castle at key points in the show (Mickey's Sorcerer's HAT is a great one).
Tinkerbell's flight (which used to take place PRIOR to the old fireworks show at MK) is now WITHIN "Wishes". She doesn't fly EVERY night, but she OFTEN flies and you should be in a position to see her.
The SWEET-SPOT for Wishes is: starting from approx. the "bridge to Tomorrowland" ...on up Main Street to the "Main Street Cinema" (Pal Mickey Store).
That is simply the "optimum viewing" area.
There are MANY other places to watch, but they are all compromises that diminish the "full effect" of the show in one way or more:
Some have little or no SOUND.
Some have obstructed views of the fireworks.
Some only allow viewing of one of the two fireworks "stages".
Some don't allow a view of the castle-front and/or Tinkerbell when she flies.
Also, the upper level of the Main Street train station (a great palce to see the "SpectroMagic" Parade) is a tempting but a not-so-good choice for "Wishes".
They DON'T turn off the LIGHTS on the last few buildings on this end of Main Street (or on the train platform) during the show, so the lights are in your eyes the whole time.
Another "ought-to-be-GREAT-but-ISN'T choice is from the "Noodle Station" seating area (the open-air counter-service restaurant that's between Main Street and Tomorrowland).
Not only do they NOT turn off the lights here (and the sound is not clear), most of the fireworks are hidden from view by the roof of the restaurant and/or the large PYLON that's on the bridge to Tomorrowland.
(I will say that there ARE a very few spots in this restaurant area that DO offer GOOD unobstructed views, but you MUST be in those exact spots and not mind the ceiling lights being on and the lack of good sound.)
So, if you don't MIND this, you can choose from a multitude of "viewing spots" throughout the MK.
My point is that the show is designed for "FULL EFFECT" to be seen from the "Sweet spot" areas I described. (But, yes, those can be C-R-O-W-D-E-D!)
Wishes is the only fireworks show that can be (for the most part) seen from outside the presenting park.
Good viewing can be found at the beach of the Polynesian Resort (walk along the sidewalk there until you see an view of the castle unobstructed by trees.)
The Ohana restaurant at the Poly offers good views (and they pipe in the audio of the show). Same goes for the California Grill Restaurant (and outdoor terrace) at the Contemporary Resort.
At Grand Floridian, Narcoossee'sNarcoossee's is the restaurant with the MK and Wishes views (and sound) otherwise, the GF boat dock (facing then MK) is the place.
The MK parking lot offers views (TTC is best, usually they pipe in the audio there). There are other outdoor spots for several miles in any direction of MK . But without the sound, you miss a lot of the "show".
Best analogy I can think of:
Sitting across the highway from a Drive-In Theater and "watching the movie" with binoculars. You can do it, but it LACKS something.