On scale of AssClass to Gintama, how difficult do think this series is to translate!?
It's a tough call.
I think due to Gintama being heavy on toilet humor and penis jokes, which are pretty much universal, it's a little easier to translate.
However, while PSI is also heavy with pop culture reference, Gintama is on a whole another unrivaled level on its own with those, so it requires a lot of knowledge and research. On the other hand. PSI is heavier leaning on language puns.
AssClass is easy by comparison to the two.
It's sorta like Phoenix Wright in the sense that the puns themselves aren't inherently necessary to be understood to enjoy it, but it takes a large portion of the content. With PW, instead of translating, they took the route of "localizing" it by replacing humor with script written by writers of their own. Which takes a lot more work, but end result was good.