Everyone always says Gamefreak fucked up hard with Shedinja and that wonder guard should also incorporate magic guard's effects.

Personally, I think quite the opposite. After seeing sturdy Shedinja, I think that wonder guard should block all attacks, even super effective ones, but no passive damage whatsoever. This means Shedinja is only able to be defeated by passive damage, which I think is fair since it has no innate immunities to any form of it and dies in one hit to all sources of it.

Picture unrelated.