Every show is different and deservers to be seen at least once, because every show has such different aspects to it!
-Wishes: NOW, if you want to watch in front of the castle, your best options are to do the dessert party, and move down to the hub grass to watch, OR get there early enough to watch them from the front of the castle (this meaning, if there is a parade before the fireworks, either watch the parade on Main st & move into the hub area for fireworks as it ends, OR get there right as the parade is ending)
OR: I like to watch from back in Fantasyland, WAY more space, you still get to see all the fireworks, and they're going off on all sides of you which can make things magical.
OR: watch from the Trader Sam's patio!
Fantasmic: aim to get there early. The fp doesn't do much, the dining package does, but I find it's not worth it to "waste" the money, we usually grab a qs dinner and try to line up as early as we can, then head in, do some weaving and speed walking to find a central more forward spot. They also might open up the roped off area if it doesn't fill up so you can move into it.
SW Fireworks: with the new show you'll probably want to be closer with the projections and such, so ARRIVE EARLY, swap off for bathroom breaks, grab so QS food to eat while you wait. Previously, I've always watched from the crossways streets leading down to Fant, and watched the fireworks, then booked it down to Fant. If Fant is earlier, we've done the opposite too and it worked out to get a closer spot for the fireworks!
Illuminations: This one can be trickier, any spot along the lagoon is better, but obviously you sometimes have a tree or something in your way. I haven't watched it in a while, but I know around Mexico we had a pretty clear view. I also like going up the stairs in Canada to watch it, get a pretty un blocked view there!
Dak: I haven't seen any of the new stuff, but I imagine getting there early is SUPER important for good seats!