A pity his scripts suck, then.
Well, not all of them. "The Insatiable Curiosity of Sophie" was excellent. "Twenty", judging from a quick glance through his other work, however, is more typical of his output.
Von Gotha is not alone in having poor scripts. None of the other well-known erotic comic artists seem be able to produce a good one, even when working from existing novels such as "The Story of O" and "Venus in Furs". The amateur eroticists over at http://www.renderotica.com/, are generally worse, though their erotic art, if as enthusiastic, is rarely quite so exquisite.
Script matters, if only because it lends emotional reality to the erotic adventures – a defloration scene is so much more of a turn on if we believe in the soon-to-be-ex-virgin. Better yet, a good story adds an extra layer or eroticism as it establishes itself in the reader's head. Think about prose, for example the "Story of O"; each scene is delicious, but taken in context, is also a glorious step on the descent into darkness. And finally, if erotic escapades are part of a proper story, they are easier to remember…
So, what's wrong with the average erotic comic script?
#1. Deficiency in basics
Usually, the artist is simply not a writer, and it shows. They're faking it, using misapplied techniques borrowed from Hollywood.
So, we get poor handling of exposition, clunky or overabundant dialogue, plots presented as mysteries, and over-complex world-building. The real amateurs – not Von Gotha, I hasten to add - also waste pages and pages on set-up.
#2. No running threat, so no real story
"Sophie" worked because the protagonist had something to lose – innocence and respectability – as she descended into the secret sex club. "Twenty", on the other hand, follows a similar loss of innocence, but in a society where to be a debauched swinger is not just respectable - it's actually socially mandatory.
Erotic utopias make great eye candy and one-handed daydreaming, but they don't lend themselves to a story, unless perhaps an innocent is unwillingly drawn into them. Similarly, loosely connected erotic episodes aren't really a plot of any sort.
#3. Threat not erotic
OK, I admit it, "Twenty" did eventually have a real threat, but it was of the thriller kind; Dick Dastardly is after her inheritance. Zzzzzz.
It simply isn't enough to present a thriller or love story peopled by sexy people who stop off to have sex between plot moments. "Look at the sexy super-heroine!" "Hey, the detective is shagging the witness."
Good threats in erotica are themselves erotic, such as the erotic slavery threatening Severin in "Venus in Furs" and eponymous protagonist in "Story of O", and permanent chastity threatening the hero of my male chastity belt novel.
A good threat should take the reader to a place which scares them rigid, but turns them on, or else stand between the protagonist and an erotic place.
It's tempting to say; "Find a real writer like me."
However, artists – especially those working in their spare time - like to illustrate their own vision. Fair enough - I wouldn’t write a novel to somebody else's outline.
So, in the end, it's up to the artist. There are books on general story telling – Robert McKee's "Story" is the classic used by movie script writers. There are also good books explaining how comics work, Scott McCloud's "Understanding Comics" is the obvious one.
Go read them!
EDIT: John in comments pointed out that the link is broken. Gotha's site has been down for some time, so I've linked to a Google image search instead.