I’m not sure I even should be seeking merit in shock value. Nonetheless, I tend to have positive associations for any fiction which can jolt me out of complacency. I imagine this isn’t unusual for an anime fan. Whatever our justifications, I think a fair bit of the experience of watching lots of anime for any period of time comes from asking what mad shit the Japanese can pull off next. Besides, I think there’s something of value in encountering the gap between what one’s own culture considers reasonable and the face of the acceptable elsewhere.
In practise though the professionally shocking anime series are more often formulaic - they have a precise species of outrage to commit, and they dutifully fill in their quota of revolting displays week by week.
One episode of Highschool of the Dead, or Panty & Stocking with Garterbelt, sprung on an unsuspecting innocent, a single slice of madness caught while skimming tv channels late at night, an oddity found when searching the contents of someone else’s PC, now that’d be shocking. For the committed gaijin fan, working through the series wholesale, the predictability neuters that value. We’d all seen PSG’s aesthetic before it even aired, and so far it’s only in the second half of episode 5 that the show has substantially broken from its own pattern. We aren’t really discomforted if we’re in on the joke.

I was busy trying to decide whether HSotD or PSG was worse(since I think I do know which is better). PSG is maybe the more uncomfortable for anime fans, in that it deviates from the customary nature of our fix, being pointedly Western (and even subverting magical girl tropes in a decidedly malicious manner). But if that show confounds expectations the fact remains that HSotD was genuinely loathsome, in its cheery way. Loathsome because of the things which made it most conventional as anime (the gender roles, the attitude to violence). For a stranger, I imagine it’s got much more discomfort in it.
Shock, I persist in believing, can be worthwhile. It can break down barriers. HSotD though was merely playing striptease tactics. On the other hand PSG is only shocking because of where it’s from. Looking beyond the Gainax signature it’s a rather nostalgic and reference-heavy slice of old school puerility.
So while one show is a late night adaptation of a pornographer’s experiment with pulp horror, and the other’s a left-field turn from a thoroughbred creative institution, neither, I’d argue, uses shock tactics meaningfully.
In fact that’s something which is terribly hard to do when you’re committed to a serial schedule. Maybe Shigurui did it, by anchoring itself to a concrete target in samurai ideology. I think the Berserk anime succeeded in doing the job by cutting and cropping so that the more psychotic excesses of the original manga were largely confined to one pair of quite horrifying episodes.
PSG, HSotD, they deliver week to week. They do well, they are funny, and I wouldn’t seek to deny their merits. But any appearance of transgressive value is misleading. The shock comes but once, and then we settle into true predictability. Is that a wanking joke there Gainax? What larks.