As you might expect, a lot of international releases make it to this list. You can largely thank NISA for that. But worry not, there are some atrocious Japanese boxes to share as well!
There are two things I don't go out of my way to beat up on. The first is art style -- there is one entry on this list that's an exception, but I'd prefer to not be too hard on Gust's more amateurish works overall. The second is that I don't go for "the best" style rereleases that put the original boxart in an ugly frame.
10. Karyuujou
There are a number of older Gust box arts that I would consider low hanging fruit, but this is the worst of them. It's just text on a bright red background; hard to be less appealing. The game itself is also fairly unknown, even among its contemporaries, so I'm sure this evoked a strong "what is this" reaction, and even having played a few minutes of it I'm not sure what to tell you!
9. Atelier Iris NISA
The very first NISA crapshoot. It's literally just plain character art of Iris and Klein on top of some generic background, which is basically most of what NISA does in general. Why they couldn't get the better art that very obviously existed is beyond me.
8. Ar tonelico 2 NISA
In a certain sense, I think all the overseas Ar tonelico boxes belong here, but the second is my least favorite of the lot. All three Japanese Ar tonelico boxes had the primary characters in an interesting decorative frame and was a very cute theme to hold for all three games. This box is just a couple different pieces of art photoshopped together. I chose the EU version over NA for this list because I think it's just a tiny bit worse.
7. Atelier Meruru NISA
This is a box I haven't thought about in years, as I own the limited edition that comes with actually good art. This mess is another NISA special where they lazily photoshop character art together. While Mimi is popular enough, her appearance is rather questionable over more notable characters, and Lias being there is honestly just hilarious!
6. Mana Khemia 2 Gust Best Price
Breaking that NISA streak with a pretty silly one from Japan. The art itself is okay, but what's with the characters lazily pasted on top of the logo? They distract from the mood of the art quite a bit. I know the art doesn't show off the characters well, but if you're concerned about that pick something else!
5. Atelier Marie + Elie PS2
Between Marie and Elie, there's quite a bit of nice art to go around. They have reliable, good artists. I think this choice is rather baffling.
4. Atelier Rorona NA
WEEB ALERT WEEB ALERT HIDE YOUR CUTE ANIME GIRLS
They made this box as bland as possible to not show off how utterly girly and weeb it actually is. Wonder if that tactic did any good for their sales? We may never know. Thanks for one last ugly box NISA!
3. Atelier Iris 3
For as similar in mood as this is to Rorona, this hazy looking box is straight from Gust's original Iris 3 release. Every other version of Iris 3 outside of these two is better.
2. Atelier Lulua
There was no saving this cover and I can't believe this bad wagon and horse combo is on every standard version of the game. Some versions try to crop the horse out more at least! There was for sure cuter art of this game lying around, and you can't just save all of it for your premium boxes, Gust! Give your plebeian copies some love, goddamn.
1. Atelier Dusk DX + Atelier Mysterious DX Play Asia
Play Asia is the distributor of the only physical English edition of these particular games. Thus, these are basically collector's pieces. For being that sort of thing, these two boxes sure are very ugly and low effort. As they're essentially the exact same box -- three "covers" with three logos lazily slapped together, they share the number one spot.