I think they are DEFINITELY the same. Here's why...

Look at the differences between pastels. Let's take Lemon Pastels as an example. How many different "grades" or "shades" of lemon pastels are there? How many combos are there with lemon pastels that look different than each other?

How about the difference between a bumblebee and a bumblebee? There can be a wide array of differences on them, but they're both spider pastels. They may have different characteristics--like spots, no spots, high white, low white, high yellow, low yellow, high gold, low gold, thin stripes, almost no stripes, completely different head patterns, etc.... BUT, they are ALL pastel spiders!

The same thing is with mystics and phantoms. If I have 2 different mojaves, say a super reduced/blushed, vs. a really contrasted busy pattern, and I pair a mystic with both of them, do you think the potions would look the same? I don't. But it doesn't change the fact that they are both mystic potions. There are way more things that play into the look of the snake than a single mystic or phantom gene.

Anyway, the point is that mystics and potions are so similarly close, that I can't see how anyone can justify calling them different morphs. I'd like to see a phantom paired with a mojave one year, and a mystic paired with the same mojave the next year. Then I'd like to see the comparison of those babies. I'd bet the similarities would be even closer than what potion/passion pictures are available online to view.